Set MacOS and Windows Go versions to 1.19

Author: smowton

.github/workflows/go-tests.yml

@@ -57,10 +57,10 @@ jobs:
     name: Test MacOS
     runs-on: macos-latest
     steps:
-      - name: Set up Go 1.18.1
+      - name: Set up Go 1.19
         uses: actions/setup-go@v3
         with:
-          go-version: 1.18.1
+          go-version: 1.19
         id: go
 
       - name: Check out code
@@ -87,10 +87,10 @@ jobs:
     name: Test Windows
     runs-on: windows-2019
     steps:
-      - name: Set up Go 1.18.1
+      - name: Set up Go 1.19
         uses: actions/setup-go@v3
         with:
-          go-version: 1.18.1
+          go-version: 1.19
         id: go
 
       - name: Check out code