feat: add test pattern

.github/workflows/test.yml

@@ -32,3 +32,17 @@ jobs:
 
       - name: Check diff
         run: git diff
+
+  not_semver:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: ./
+        id: depup
+        with:
+          file: testdata/testfile
+          version_name: TMUX_VERSION
+          repo: tmux/tmux
+
+      - name: Check diff
+        run: git diff

testdata/testfile

@@ -14,3 +14,5 @@ The above version should be updated to the latest version with this action.
 Other test cases.
 
 REDPEN_VERSION=1.10.1
+
+TMUX_VERSION=3.0