ci: upgrade to Go 1.19.1

Go released 1.18.6 + 1.19.1 today which fix a couple
CVEs. (`golang.org/x/net` also has a related fix.)

This jumps from 1.18.5 -> 1.19.1 since it was on the
to-do list regardless :)

Signed-off-by: Milas Bowman <milas.bowman@docker.com>

.github/workflows/ci.yml

@@ -19,7 +19,6 @@ on:
         default: "false"
 
 env:
-  GO_VERSION: "1.18.5" # for non sandboxed e2e tests
   DESTDIR: "./bin"
   DOCKER_CLI_VERSION: "20.10.17"
 
@@ -143,7 +142,8 @@ jobs:
         name: Set up Go
         uses: actions/setup-go@v3
         with:
-          go-version: ${{ env.GO_VERSION }}
+          go-version-file: 'go.mod'
+          check-latest: true
           cache: true
       -
         name: Setup docker CLI