CI: Fetch tags during checkout

Protodec currently requires at least one git tag in order to identify
its version

Author: syeopite

.github/workflows/ci.yml

@@ -36,6 +36,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@v5
+        with:
+          fetch-tags: true
 
       - name: Install Crystal
         uses: crystal-lang/[email protected]
@@ -54,6 +56,8 @@ jobs:
 
     steps:
       - uses: actions/checkout@v5
+        with:
+          fetch-tags: true
 
       - name: Install Crystal
         uses: crystal-lang/[email protected]