Fork pgtap-docker to support arm64 (#2411)

* feat(sql): Fork pgtap to support arm64

This forks pgtap-docker and builds the image locally,
and updates our references to use our forked image.

* fixup! feat(sql): Fork pgtap to support arm64

testing/dbtest/pgtap-docker/Makefile

@@ -0,0 +1,21 @@
+REGISTRY_NAME ?= docker.io/hashicorpboundary
+TEST_IMAGE_NAME = pgtap
+PG_VERSION ?= 13
+
+# Before running this target a builder instance needs to be setup, ie:
+#  docker buildx create --driver docker-container --use
+.PHONY: docker-build
+docker-build:
+	docker buildx build \
+		--platform linux/amd64,linux/arm64 \
+		-t $(REGISTRY_NAME)/$(TEST_IMAGE_NAME):$(PG_VERSION) \
+		--build-arg PG_VERSION=$(PG_VERSION) \
+		-f Dockerfile .
+
+.PHONY: docker-load
+docker-load:
+	docker buildx build \
+		--load \
+		-t $(REGISTRY_NAME)/$(TEST_IMAGE_NAME):$(PG_VERSION) \
+		--build-arg PG_VERSION=$(PG_VERSION) \
+		-f Dockerfile .