GitHub: remove Go env variable override

For some reason we used to override the GOCACHE and GOPATH variables
earlier. This now causes the updated cache action not to pick up any
caches. As the overrides shouldn't be needed anymore, we remove them.

.github/actions/setup-go/action.yml

@@ -26,3 +26,8 @@ runs:
         key: ${{ runner.os }}-go-${{ env.GO_VERSION }}-${{ hashFiles('**/go.sum') }}
         restore-keys: |
           ${{ runner.os }}-go-${{ env.GO_VERSION }}-
+
+    - name: set GOPATH
+      shell: bash
+      run: |
+        echo "GOPATH=$(go env GOPATH)" >> $GITHUB_ENV

.github/workflows/main.yml

@@ -18,9 +18,6 @@ defaults:
     shell: bash
 
 env:
-  # go needs absolute directories, using the $HOME variable doesn't work here.
-  GOCACHE: /home/runner/work/go/pkg/build
-  GOPATH: /home/runner/work/go
   BITCOIN_VERSION: "23.0"
 
   # If you change this value, please change it in the following files as well:
@@ -236,9 +233,6 @@ jobs:
   windows-integration-test:
     name: run windows itest
     runs-on: windows-latest
-    env:
-      GOCACHE: ${{ github.workspace }}/go/pkg/build
-      GOPATH: ${{ github.workspace }}/go
     steps:
       - name: git checkout
         uses: actions/checkout@v3
@@ -320,9 +314,6 @@ jobs:
   new-windows-integration-test:
     name: run new windows itest
     runs-on: windows-latest
-    env:
-      GOCACHE: ${{ github.workspace }}/go/pkg/build
-      GOPATH: ${{ github.workspace }}/go
     steps:
       - name: git checkout
         uses: actions/checkout@v3