Run Go integration tests on all operating systems

Bugs can sometimes be operating system-specific, so it's important to test with all of them. This was done in the source
workflow, but ended up being lost when the integration testing functionality was moved to a dedicated workflow.

Author: per1234

workflow-templates/dependabot/workflow-template-copies/.github/workflows/test-go-integration-task.yml

@@ -34,7 +34,14 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        operating-system:
+          - ubuntu-latest
+          - windows-latest
+          - macos-latest
+
+    runs-on: ${{ matrix.operating-system }}
 
     steps:
       - name: Checkout repository

workflow-templates/test-go-integration-task.yml

@@ -34,7 +34,14 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        operating-system:
+          - ubuntu-latest
+          - windows-latest
+          - macos-latest
+
+    runs-on: ${{ matrix.operating-system }}
 
     steps:
       - name: Checkout repository