Use newer version of setup-go and remove cache step

`setup-go` implements the same caching in newer versions, which is on by default

Author: mbg

.github/workflows/ci.yml

@@ -12,22 +12,14 @@ jobs:
         steps:
 
             - name: Set up Go 1.x
-              uses: actions/setup-go@v2
+              uses: actions/setup-go@v5
               with:
                   go-version: ^1.13
               id: go
 
             - name: Checkout repository
               uses: actions/checkout@v2
 
-            - name: Set up cache
-              uses: actions/cache@v2
-              with:
-                path: ~/go/pkg/mod
-                key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
-                restore-keys: |
-                  ${{ runner.os }}-go-
-
             - name: Get dependencies
               run: go get -v -t -d .