Switch to GOTOOLCHAIN env setting from gimme

hack/setup-go.sh

@@ -13,29 +13,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# script to setup go version with gimme as needed
+# script to setup go version as needed
 # MUST BE RUN FROM THE REPO ROOT DIRECTORY
 
 # read go-version file unless GO_VERSION is set
 GO_VERSION="${GO_VERSION:-"$(cat .go-version)"}"
 GO_IMAGE=public.ecr.aws/docker/library/golang:$GO_VERSION
 
-# we don't actually care where the .env files are
-# however, GIMME_SILENT_ENV doesn't trigger re-generating a .env if it
-# already exists and isn't "silent" (no `go version` command in it)
-# so we fix that by changing where the .env is written, ensuring ours
-# is generated from this repo and silent.
-export GIMME_ENV_PREFIX=./bin/.gimme/
-export GIMME_SILENT_ENV=y
-
-# only setup go if we haven't set FORCE_HOST_GO, or `go version` doesn't match
-# go version output looks like:
-# go version go1.14.5 darwin/amd64
-if ! ([ -n "${FORCE_HOST_GO:-}" ] || \
-      (command -v go >/dev/null && [ "$(go version | cut -d' ' -f3)" = "go${GO_VERSION}" ])); then
-    # eval because the output of this is shell to set PATH etc.
-    eval "$(hack/third_party/gimme/gimme "${GO_VERSION}")"
-fi
+# gotoolchain
+# https://go.dev/doc/toolchain
+export GOSUMDB="sum.golang.org"
+export GOTOOLCHAIN=go${GO_VERSION}
 
 # force go modules
 export GO111MODULE=on