Add codecov configuration file and simplify coverage profile generation

A codecov.yml configuration file has been added to specify the coverage target and other codecov settings. The CI pipeline has also been streamlined to directly generate the coverage profile without using grep for filtering ignored code paths. This makes it easier to understand and maintain the testing and coverage reporting process.

.github/workflows/codecov.yml

@@ -36,12 +36,9 @@ jobs:
         go-version: ${{ matrix.go }}
     - name: Run Tests
       run: |
-        go test -v -race --coverprofile=coverage.coverprofile.tmp --covermode=atomic ./...
+        go test -v -race --coverprofile=coverage.coverprofile --covermode=atomic ./...
-    - name: Remove ignored code from coverage profile
-      run: |
-        grep -v -E '(apg-go/cmd/apg/apg.go|apg-go/example-code)' coverage.coverprofile.tmp > coverage.coverprofile
     - name: Upload coverage to Codecov
       if: success() && matrix.go == '1.22' && matrix.os == 'ubuntu-latest'
       uses: codecov/codecov-action@v3
       with:
-        token: ${{ secrets.CODECOV_TOKEN }} # not required for public repos
+        token: ${{ secrets.CODECOV_TOKEN }} # not required for public repos

codecov.yml

@@ -0,0 +1,26 @@
+# SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
+#
+# SPDX-License-Identifier: CC0-1.0
+
+coverage:
+  status:
+    project:
+      default:
+        target: 85%
+        threshold: 5%
+        base: auto 
+        if_ci_failed: error
+        only_pulls: false
+    patch:
+      default:
+        target: 80%
+        base: auto
+        if_ci_failed: error
+        threshold: 5%
+
+comment:
+  require_changes: true
+
+ignore:
+  - "cmd/apg"
+  - "example-code"