fix(prepare): use correct version for prereleases

this fix requires that all `-` be replaced by `.` in the gem version to avoid version inconsistencies

src/__tests__/prepare.test.js

@@ -55,7 +55,7 @@ describe('when the version.rb contains a prerelease version', () => {
     expect(versionContents).toEqual(`# frozen_string_literal: true
 
 module TestGem
-  VERSION = '1.0.0-alpha.1'
+  VERSION = '1.0.0.alpha.1'
 end
 `);
   });

src/__tests__/verifyConditions.test.js

@@ -48,7 +48,7 @@ describe('when the gemspec has no name defined', () => {
   });
 });
 
-it('finds the version file', async () => {
+it('verifies the version file', async () => {
   const { versionFile } = await verifyConditions(
     {},
     { cwd: validCwd, env: defaultEnv },

src/prepare.js

@@ -6,7 +6,12 @@ const { VERSION_REGEX } = require('./common');
 const writeVersion = async ({ versionFile, nextVersion, logger, cwd }) => {
   const fullVersionPath = path.resolve(cwd, versionFile);
   const versionContents = await readFile(fullVersionPath, 'utf8');
-  const newContents = versionContents.replace(VERSION_REGEX, `$1${nextVersion}$2`);
+  const newContents = versionContents.replace(
+    VERSION_REGEX,
+    // Rubygems replaces all `-` with `.pre.`, which causes odd version differences between tags/releases
+    // and the published gem version. Replacing `-` with `.` is a smaller difference.
+    `$1${nextVersion.replace('-', '.')}$2`,
+  );
   logger.log('Writing version %s to `%s`', nextVersion, versionFile);
   await writeFile(fullVersionPath, newContents, 'utf8');
 };