Release: v3.0.0-beta1 (#411)

## Notable Changes

While we always seek to minimize breaking changes, there is a
substantial delta between Cloud Functions v1 and Cloud Functions v2,
such that the GitHub Action was mostly rewritten.

- "v3" supports 2nd generation Cloud Functions (`GEN_2`). 1st generation
Cloud Functions _may_ work, but **`GEN_1` is not supported**. Use
`google-github-actions/deploy-cloud-functions@v2` for 1st generation
functions.

- "files" inputs such as `environment_variables_file` have been removed.
To source values from a file, read the file in a prior step and set an
output. There are many community-sponsored GitHub Actions that provide
this functionality.

- "memory" is now specified as a string with a suffix (e.g. "5Mb")
instead of assuming megabytes.

- "secret_env_vars" and "secret_volumes" have been combined into a
single "secrets" input which accepts environment variable keys or
filepaths.

- Various fields were renamed to match the "v2" API, such as
"service_account" and "min/max_instance_count".

- Labels, environment variables, and secrets are still declarative, but
they are not modified if no values are given. You can explicitly empty
the value by setting the input to the literal string "{}".

- Functions are only served over HTTPS (no HTTP). This is a requirement
for Cloud Functions v2.

- Since Cloud Functions v2 uses EventArc, you may need to enable the
EventArc API and re-configure triggers (many inputs have changed to
match the new API specification).


In accordance with our support policy, when "v3" is released as GA, we
will stop supporting "v1" and continue to support "v2" and "v3".

package.json

@@ -1,6 +1,6 @@
 {
   "name": "deploy-cloud-functions",
-  "version": "2.1.0",
+  "version": "3.0.0",
   "description": "Deploy a Cloud Function",
   "main": "dist/index.js",
   "scripts": {