Bug: Changelog didn't have the version (#324)

I introduced a bug when refactoring the build pipleline, wherein there
wasn't a `./version` file anymore which stored the current version
number, such that it could be shared across build steps.

Therefore there was no version on the changelog! This fixes that by
creating a `version` taget for the Makefile and pushing that into a file
the changelog generator can use.

Work on #313

build/Makefile

@@ -42,6 +42,10 @@ docker_in_docker := -v /var/run/docker.sock:/var/run/docker.sock
 help:
 	@cat $(MAKEFILE_LIST) | docker run --rm -i xanders/make-help
 
+# output the current build version
+version:
+	@echo $(package_version)
+
 # Run all tests
 test: ensure-build-image
 	docker run --rm $(common_rust_args) \

build/release/cloudbuild.yaml

@@ -33,6 +33,13 @@ steps:
       - IMAGE_NAME=${_IMAGE_TAG}
       - build
     id: build
+  - name: us-docker.pkg.dev/$PROJECT_ID/ci/make-docker
+    dir: ./build
+    entrypoint: bash
+    args:
+      - '-c'
+      - 'make version > ../version'
+    id: output-version
   - name: ferrarimarco/github-changelog-generator:1.15.2
     id: changelog
     entrypoint: sh