Update google-java-format CI

JDK 16 is now released, so mark it non-experimental and add a build for JDK
17-EA. Also add a JDK 14 build back, to prevent regressions in some Java >= 14
features that are handled differently between 14 and 16.

PiperOrigin-RevId: 368111853

.github/workflows/ci.yml

@@ -29,19 +29,19 @@ jobs:
       fail-fast: false
       matrix:
         os: [ ubuntu-latest ]
-        java: [ 15, 11 ]
+        java: [ 16, 14, 11 ]
         experimental: [ false ]
         include:
           # Only test on macos and windows with a single recent JDK to avoid a
           # combinatorial explosion of test configurations.
           - os: macos-latest
-            java: 15
+            java: 16
             experimental: false
           - os: windows-latest
-            java: 15
+            java: 16
             experimental: false
           - os: ubuntu-latest
-            java: 16-ea
+            java: 17-ea
             experimental: true
     runs-on: ${{ matrix.os }}
     continue-on-error: ${{ matrix.experimental }}