Fix: Add checkout to Build_Postfix to fix workflow building

Checkout cannot be in a self-contained action, as checkout needs to be
called before the action is invoked -- otherwise the action doesn't
exist. 🤷

.github/actions/build-postfix-exporter/action.yaml

@@ -4,10 +4,6 @@ description: 'Build the latest version of postfix-exporter'
 runs:
   using: "composite"
   steps:
-    # Checkout
-    - name: Checkout
-      uses: actions/checkout@v4
-
     - name: Checkout
       uses: actions/checkout@v4
       with:

.github/workflows/master.yml

@@ -42,6 +42,9 @@ jobs:
     needs:
       - Helm_chart_Tests
     steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
       - uses: ./.github/actions/build-postfix-exporter
         with:
           tags: |

.github/workflows/tags.yml

@@ -42,6 +42,9 @@ jobs:
     needs:
       - Helm_chart_Tests
     steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
       - uses: ./.github/actions/build-postfix-exporter
         with:
           tags: |