ci: fix fox and ghr install

Author: christophwitzko

.github/workflows/ci.yml

@@ -35,8 +35,8 @@ jobs:
         with:
           go-version: 1.16
       - run: |
-          go get github.com/mitchellh/gox
-          go get github.com/tcnksm/ghr
+          go install github.com/mitchellh/gox@latest
+          go install github.com/tcnksm/ghr@latest
       - uses: go-semantic-release/action@v1
         id: semrel
         with: