fix(versioning/github-actions): treat floating tags as equal (#42809)

* fix(versioning/github-actions): treat floating tags as equal

As noted in #42662, if a floating tag `@v2` is used, Renovate currently
tries to roll it back to `@v1`, as it doesn't see that `@v2 === @v2`.

* fix(versioning/github-actions): allow `v` prefix matching too

Author: jamietanna

lib/modules/versioning/github-actions/index.spec.ts

@@ -108,9 +108,14 @@ describe('modules/versioning/github-actions/index', () => {
       ${'1.0.0-rc'}       | ${'1.0'}     | ${false}
       ${'invalid'}        | ${'1'}       | ${false}
       ${'~latest'}        | ${'1'}       | ${false}
-      ${'1'}              | ${'1'}       | ${false}
-      ${'1.2'}            | ${'1.2'}     | ${false}
-      ${'1.2.3'}          | ${'1.2.3'}   | ${true}
+      ${'1'}              | ${'1'}       | ${true}
+      ${'1'}              | ${'v1'}      | ${true}
+      ${'v1'}             | ${'v1'}      | ${true}
+      ${'v1'}             | ${'1'}       | ${true}
+      ${'1.2'}            | ${'1.2'}     | ${true}
+      ${'1.2'}            | ${'v1.2'}    | ${true}
+      ${'v1.2'}           | ${'v1.2'}    | ${true}
+      ${'v1.2'}           | ${'1.2'}     | ${true}
       ${'1.2.4'}          | ${'1.2.3'}   | ${false}
       ${'not-semver-ver'} | ${'1'}       | ${false}
       ${'1.0.0-alpha'}    | ${'1'}       | ${false}

lib/modules/versioning/github-actions/index.ts

@@ -131,6 +131,14 @@ function isGreaterThan(x: string, y: string): boolean {
 }
 
 function matches(version: string, range: string): boolean {
+  // if we have a valid floating tag provided, and it's the same as the range, treat it as the same
+  if (
+    parseVersionCoerced(version) &&
+    massageValue(version) === massageValue(range)
+  ) {
+    return true;
+  }
+
   const v = parseVersion(version);
   if (!v) {
     return false;