[workflow] Use gcc problem matcher for Ubuntu action build (GH-18567)

.github/problem-matchers/gcc.json

@@ -0,0 +1,18 @@
+{
+    "__comment": "Taken from vscode-cpptools's Extension/package.json gcc rule",
+    "problemMatcher": [
+        {
+            "owner": "gcc-problem-matcher",
+            "pattern": [
+                {
+                    "regexp": "^(.*):(\\d+):(\\d+):\\s+(?:fatal\\s+)?(warning|error):\\s+(.*)$",
+                    "file": 1,
+                    "line": 2,
+                    "column": 3,
+                    "severity": 4,
+                    "message": 5
+                }
+            ]
+        }
+    ]
+}

.github/workflows/build.yml

@@ -87,6 +87,8 @@ jobs:
       OPENSSL_VER: 1.1.1f
     steps:
     - uses: actions/checkout@v2
+    - name: Register gcc problem matcher
+      run: echo "::add-matcher::.github/problem-matchers/gcc.json"
     - name: Install Dependencies
       run: sudo ./.github/workflows/posix-deps-apt.sh
     - name: 'Restore OpenSSL build'