chore: Revert 12.0.0 naming.

Using 'v12' is more generic and will automatically be correct when the
plugin moves to an eventual 12.0.1 or 12.1.0.

Author: BenHenning

.github/workflows/build.yml

@@ -58,7 +58,7 @@ jobs:
           npm run build
 
   build:
-    name: Build test (against pinned v12.0.0)
+    name: Build test (against pinned v12)
     # Don't run pinned version checks for PRs.
     if: ${{ !github.base_ref }}
     runs-on: ubuntu-latest

.github/workflows/test.yml

@@ -66,7 +66,7 @@ jobs:
           npm run test
 
   webdriverio_tests:
-    name: WebdriverIO tests (against pinned v12.0.0)
+    name: WebdriverIO tests (against pinned v12)
     # Don't run pinned version checks for PRs.
     if: ${{ !github.base_ref }}
     timeout-minutes: 10