Fix tests to make them compatible with non-english GPG installations

[yeraydavidrodriguez]

This will make the tests referenced in #66 compatible with non-english GPG installations.

To do so, it replaces the full expected string with a RegExp in which the words "gpg:", RSA and the fingerprint are checked.

Although we cannot assure that it creates false-positive tests (maybe considering valid a string reporting an error with the RSA key), I think it is very unlikely, but the possibility of the user having a non-english GPG installation is very high.

[github-actions]

MegaLinter status: ⚠️ WARNING

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ ACTION	actionlint	4		0	0.14s
✅ COPYPASTE	jscpd	yes		no	1.36s
✅ CREDENTIALS	secretlint	yes		no	0.78s
✅ GIT	git_diff	yes		no	0.01s
✅ JAVASCRIPT	standard	1	0	0	1.12s
✅ JSON	eslint-plugin-jsonc	7	0	0	0.77s
✅ JSON	jsonlint	7		0	1.55s
✅ JSON	prettier	7	1	0	1.06s
✅ JSON	v8r	7		0	5.97s
⚠️ MARKDOWN	markdownlint	2	0	1	0.31s
✅ MARKDOWN	markdown-link-check	2		0	4.96s
✅ MARKDOWN	markdown-table-formatter	2	2	0	0.23s
✅ SPELL	cspell	80		0	2.84s
✅ SPELL	misspell	80	2	0	0.13s
✅ TYPESCRIPT	eslint	54	2	0	12.35s
✅ YAML	prettier	7	0	0	1.79s
✅ YAML	v8r	7		0	7.34s
✅ YAML	yamllint	7		0	0.25s

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