fix: yml files are skipped by circleci hook

[diofeher]

While I was testing these hooks, it seems the changes on yml files were never recognized on the .circleci folder:

CircleCI config validation...........................(no files to check)Skipped

when .circleci/config.yml was changed.

I've made this small change and then I was able to see the files being recognized by pre-commit.

CircleCI config validation...............................................Failed
- hook id: circleci-config-validate
- exit code: 1

Error: config compilation contains errors: config compilation contains errors:
	- Unable to parse YAML
	- while scanning a simple key
	-  in 'string', line 5, column 1:
	-     asads:A1
	-     ^
	- could not find expected ':'
	-  in 'string', line 6, column 3:
	-       :

[diofeher]

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