Update CI to no longer build with Go 1.18

Signed-off-by: Paul Balogh <javaducky@gmail.com>

Author: javaducky

.github/workflows/all.yml

@@ -40,7 +40,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        go-version: [1.18.x, 1.19.x, 1.20.x, tip]
+        go-version: [1.19.x, 1.20.x, tip]
         platform: [ubuntu-latest, windows-latest]
     runs-on: ${{ matrix.platform }}
     steps: