ci(release): move the "scripts/" folder under the ".github/" one (#527)

A new issue can be observed due to the following change: #519.

This time, it has been observed that the `generate-plugin.sh` script is no longer at the expected location, that's being said under the `.github/scripts` folder.

The thrown error after executing the `semantic-release` command through CI is the following one:

```
| [7:49:35 PM] [semantic-release] [@semantic-release/exec] › ℹ  Call script ./scripts/generate-plugin.sh 3.0.3
| /bin/sh: 1: ./scripts/generate-plugin.sh: not found
| [7:49:35 PM] [semantic-release] › ✘  Failed step "prepare" of plugin "@semantic-release/exec"
| [7:49:35 PM] [semantic-release] › ✘  An error occurred while running semantic-release: Error: Command failed with exit code 127: ./scripts/generate-plugin.sh 3.0.3
| /bin/sh: 1: ./scripts/generate-plugin.sh: not found
|     at makeError (/mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/execa/lib/error.js:60:11)
|     at handlePromise (/mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/execa/index.js:118:26)
|     at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
|     at async module.exports (/mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/@semantic-release/exec/lib/exec.js:16:11)
|     at async prepare (/mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/@semantic-release/exec/index.js:54:5)
|     at async validator (file:///mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/semantic-release/lib/plugins/normalize.js:36:24)
|     at async file:///mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/semantic-release/lib/plugins/pipeline.js:38:36
|     at async file:///mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/semantic-release/lib/plugins/pipeline.js:32:5
|     at async pluginsConfigAccumulator.<computed> [as prepare] (file:///mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/semantic-release/lib/plugins/index.js:87:11)
|     at async run (file:///mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/semantic-release/index.js:202:3) {
|   shortMessage: 'Command failed with exit code 127: ./scripts/generate-plugin.sh 3.0.3',
|   command: './scripts/generate-plugin.sh 3.0.3',
|   escapedCommand: '"./scripts/generate-plugin.sh 3.0.3"',
|   exitCode: 127,
|   signal: undefined,
|   signalDescription: undefined,
|   stdout: '',
|   stderr: '/bin/sh: 1: ./scripts/generate-plugin.sh: not found',
|   failed: true,
|   timedOut: false,
|   isCanceled: false,
|   killed: false,
|   pluginName: '@semantic-release/exec'
| }
| Error: Command failed with exit code 127: ./scripts/generate-plugin.sh 3.0.3
| /bin/sh: 1: ./scripts/generate-plugin.sh: not found
|     at makeError (/mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/execa/lib/error.js:60:11)
|     at handlePromise (/mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/execa/index.js:118:26)
|     at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
|     at async module.exports (/mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/@semantic-release/exec/lib/exec.js:16:11)
|     at async prepare (/mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/@semantic-release/exec/index.js:54:5)
|     at async validator (file:///mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/semantic-release/lib/plugins/normalize.js:36:24)
|     at async file:///mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/semantic-release/lib/plugins/pipeline.js:38:36
|     at async file:///mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/semantic-release/lib/plugins/pipeline.js:32:5
|     at async pluginsConfigAccumulator.<computed> [as prepare] (file:///mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/semantic-release/lib/plugins/index.js:87:11)
|     at async run (file:///mnt/c/Users/loicd/IdeaProjects/mc-jobs-reborn-patch-place-break/.github/node_modules/semantic-release/index.js:202:3) {
|   shortMessage: 'Command failed with exit code 127: ./scripts/generate-plugin.sh 3.0.3',
|   command: './scripts/generate-plugin.sh 3.0.3',
|   escapedCommand: '"./scripts/generate-plugin.sh 3.0.3"',
|   exitCode: 127,
|   signal: undefined,
|   signalDescription: undefined,
|   stdout: '',
|   stderr: '/bin/sh: 1: ./scripts/generate-plugin.sh: not found',
|   failed: true,
|   timedOut: false,
|   isCanceled: false,
|   killed: false,
|   pluginName: '@semantic-release/exec'
```

Since the idea of moving the `scripts/` folder under the `.github/` one permits to refine even more the root repository directory, then there is no reason for wanting to change the expectations. Furthermore, doing so highlight the fact that scripts under the `.github/scripts/` directory are specific to GitHub Actions workflows. So, this fix consist only on moving the script file in the right location.