fix: switch to go install from go get

This no longer works as of go 1.18: https://go.dev/doc/go-get-install-deprecation

tests.mk

@@ -144,7 +144,9 @@ ci-go-coverage-plugin:
 		-w $(GO_REPO_ROOT) \
 		$(BUILD_IMAGE) \
 		bash -c "cd plugins/$(PLUGIN_NAME) && \
-			go get github.com/onsi/gomega github.com/schrej/godacov github.com/haya14busa/goverage && \
+			go get github.com/onsi/gomega && \
+			go install github.com/schrej/godacov && \
+			go install github.com/haya14busa/goverage && \
 			goverage -v -coverprofile=./../../test-results/coverage/$(PLUGIN_NAME).out && \
 			(godacov -r ./../../test-results/coverage/$(PLUGIN_NAME).out -c $$CIRCLE_SHA1 -t $$CODACY_TOKEN || true)" || exit $$?