function getFirstVersionOfDeletion(filePath) {
	const deletionCommit = getCommitDeletingFile(filePath),
		tags = execSilent(`git tag --contains ${deletionCommit}`);

	return splitCommandResultToLines(tags)
		.map(version => semver.valid(version.trim()))
		.filter(version => version)
		.sort(semver.compare)[0];
}
Gets the first version number where a given file is no longer present.
@param {string} filePath The path to the deleted file.
@returns {string} The version number.