feat: introduce FRESH version regex

src/utils/fresh-version-regex.coffee

@@ -0,0 +1,23 @@
+###*
+Defines a regex suitable for matching FRESH versions.
+@module file-contains.js
+###
+
+# Set up a regex that matches all of the following:
+#
+#   - FRESH
+#   - JRS
+#   - FRESCA
+#   - FRESH@1.0.0
+#   - FRESH@1.0
+#   - FRESH@1
+#   - JRS@0.16.0
+#   - JRS@0.16
+#   - JRS@0
+#
+# Don't use a SEMVER regex (eg, NPM's semver-regex) because a) we want to
+# support partial semvers like "0" or "1.2" and b) we'll expand this later to
+# support fully scoped FRESH versions.
+
+module.exports = () ->
+  RegExp '^(FRESH|FRESCA|JRS)(?:@(\\d+(?:\\.\\d+)?(?:\\.\\d+)?))?$'