Improve pre-commit hook keeping version in sync to handle beta versions

The git pre-commit hook we've been using the last years to keeping
.version found in `package.json` in sync with the .version field
exposed by the source code, did not handle version numbers often
used for pre-relases like `beta | new` etc.

Therefore making sure it searches for versions that also contains
characters, not only numbers separated by dots. That will make sure
the following is also seen as valid versions: `3.2.0-beta.0`,
whereas before the `-beta` part would cause trouble.

hooks/pre-commit

@@ -78,7 +78,7 @@ class Bumper
 end
 
 bumper = Bumper.new([
-	Source.new('mustache.mjs', /version: '([\d\.]*)'/),
-	Source.new('mustache.js.nuspec', /<version>([\d\.]*)<\/version>/),
+	Source.new('mustache.mjs', /version: '([^']+)'/),
+	Source.new('mustache.js.nuspec', /<version>([^<]+)<\/version>/),
 ])
 bumper.start