Adding in testing of multiple versions for Bazel in Github Action and clarified tested/supported versions of Bazel in the README

Author: bhers4

.bazelversion

@@ -0,0 +1 @@
+6.5.0

.github/workflows/release_build.yml

@@ -43,27 +43,45 @@ jobs:
     strategy:
       matrix:
         include:
+          # Do a singular build for Bazel 4.2.2 to test Bazel 4.2.2.
+          - os: ubuntu-latest
+            compiler: gcc
+            version: 11
+            bazel: 4.2.2
+          # Run Bazel 6.5.0 on all compilers versions.
           - os: ubuntu-latest
             compiler: gcc
             version: 9
+            bazel: 6.5.0
           - os: ubuntu-latest
             compiler: gcc
             version: 10
+            bazel: 6.5.0
+          - os: ubuntu-latest
+            compiler: gcc
+            version: 11
+            bazel: 6.5.0
           - os: ubuntu-latest
             compiler: clang
             version: 14
+            bazel: 6.5.0
     steps:
     - uses: actions/checkout@v2
 
     # Compile.
-    - name: Install Bazel 4.2.2
+    - name: Install Bazel ${{ matrix.bazel }}
       uses: abhinavsingh/setup-bazel@v3
       with:
-        version: 4.2.2
+        version: ${{ matrix.bazel }}
 
     - name: Setup Environment (Linux)
       if: matrix.os == 'ubuntu-latest'
       run: |
+        # Just for Github action builds set USE_BAZEL_VERSION to override the
+        # .bazelversion file so we can test different Bazel versions even though
+        # the recommended Bazel version will be in the .bazelversion file.
+        echo "USE_BAZEL_VERSION=${{ matrix.bazel }}" >> $GITHUB_ENV
+
         if [[ "${{ matrix.compiler }}" == "gcc" ]]; then
           sudo apt install gcc-${{ matrix.version }} g++-${{ matrix.version }}
           sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-${{ matrix.version }} 100 \

README.md

@@ -46,7 +46,7 @@ One FusionEngine or a Point One device (Atlas, Quectel LG69T, etc.), please cont
 
 #### C++ Support
 - C++11 or later
-- CMake 3.x or Bazel 3.x
+- CMake 3.x or Bazel 4.x-6.x (tested with Bazel versions 4.2.2-6.5.0, Bazel 8+ not currently supported)
 - GCC, Clang, or Microsoft Visual Studio
 
 #### Python Support