Update dependencies (#79)

* Update dependencies

gvisor was not updated to the latest version, because it did not
compile.

* actions: Update go version to 1.20

* docker: Update go version to 1.20

.github/workflows/test.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Setting up Go
         uses: actions/setup-go@v2
         with:
-          go-version: 1.19
+          go-version: "1.20"
       - name: Install dependencies
         run: sudo apt install wireguard curl
       - name: Building wireproxy