Stream go test logs

Go will only stream test logs if it is testing a single module at a
time, otherwise it will buffer the logs to the end and then display
them. This causes issues for CI as it means there's no idea what is
happening at the moment and the logs will be missing if the run is
cancelled.

See golang/go#27826.

Author: wjam

GNUmakefile

@@ -30,8 +30,9 @@ clean:
 	@echo "Deleting local provider binary"
 	rm -rf $(BIN)
 
+# `-p=1` added to avoid testing packages in parallel which causes `go test` to not stream logs as they are written
 testacc:
-	TF_ACC=1 go test ./... -v $(TESTARGS) -timeout 360m -parallel=$(TEST_PARALLELISM)
+	TF_ACC=1 go test ./... -v $(TESTARGS) -timeout 360m -p=1 -parallel=$(TEST_PARALLELISM)
 
 install_local: build
 	@echo "Installing local provider binary to plugins mirror path $(PLUGINS_PATH)/$(PLUGINS_PROVIDER_PATH)"