gha: update go versions to 1.18, 1.19

Note that go1.13 has reached EOL a long time ago; perhaps we should
consider dropping it, but it may be okay to continue testing for
backward compatibility.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Author: thaJeztah

.github/workflows/ci.yaml

@@ -14,7 +14,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu, macos, windows]
-        golang: ['1.13', '1.16', '1.17']
+        golang: ['1.13', '1.18', '1.19']
         # currently, we cannot run non-x86_64 machines on GitHub Actions cloud env.
     runs-on: ${{ matrix.os }}-latest
     name: CI golang ${{ matrix.golang }} on ${{ matrix.os }}