feat: set release_status to Production/Stable (#8)

Release-As: 1.0.0

Proposed release: **GA**

## Instructions

Check the lists below, adding tests / documentation as required. Once all the "required" boxes are ticked, please create a release and close this issue.

## Required

- [x] 28 days elapsed since last beta release with new API surface (last release on [2/5/2020](https://github.com/googleapis/python-monitoring/releases/tag/v0.34.0))
- [x] Server API is GA ([v3](https://github.com/googleapis/python-monitoring/tree/master/google/cloud/monitoring_v3))
- [x] Package API is stable, and we can commit to backward compatibility
- [x] All dependencies are GA

## Optional

- [ ] Most common / important scenarios have descriptive samples
- [ ] Public manual methods have at least one usage sample each (excluding overloads)
- [ ] Per-API README includes a full description of the API
- [ ] Per-API README contains at least one “getting started” sample using the most common API scenario
- [ ] Manual code has been reviewed by API producer
- [ ] Manual code has been reviewed by a DPE responsible for samples
- [ ] 'Client Libraries' page is added to the product documentation in 'APIs & Reference' section of the product's documentation on Cloud Site

Author: busunkim96

.repo-metadata.json

@@ -4,9 +4,9 @@
   "product_documentation": "https://cloud.google.com/monitoring/docs",
   "client_documentation": "https://googleapis.dev/python/monitoring/latest",
   "issue_tracker": "https://issuetracker.google.com/savedsearches/559785",
-  "release_level": "alpha",
+  "release_level": "ga",
   "language": "python",
   "repo": "googleapis/python-monitoring",
   "distribution_name": "google-cloud-monitoring",
   "api_id": "monitoring.googleapis.com"
-}
+}

README.rst

@@ -1,7 +1,7 @@
-Python Client for Stackdriver Monitoring API (`Alpha`_)
+Python Client for Stackdriver Monitoring API
 =======================================================
 
-|pypi| |versions| 
+|ga| |pypi| |versions| 
 
 `Stackdriver Monitoring API`_: Manages your Stackdriver Monitoring data and
 configurations. Most projects must be associated with a Stackdriver account,
@@ -10,7 +10,8 @@ with a few exceptions as noted on the individual method pages.
 - `Client Library Documentation`_
 - `Product Documentation`_
 
-.. _Alpha: https://github.com/googleapis/google-cloud-python/blob/master/README.rst
+.. |ga| image:: https://img.shields.io/badge/support-GA-gold.svg
+   :target: https://github.com/googleapis/google-cloud-python/blob/master/README.rst#general-availability
 .. |pypi| image:: https://img.shields.io/pypi/v/google-cloud-monitoring.svg
    :target: https://pypi.org/project/google-cloud-monitoring/
 .. |versions| image:: https://img.shields.io/pypi/pyversions/google-cloud-monitoring.svg

setup.py

@@ -27,7 +27,7 @@
 # 'Development Status :: 3 - Alpha'
 # 'Development Status :: 4 - Beta'
 # 'Development Status :: 5 - Production/Stable'
-release_status = "Development Status :: 3 - Alpha"
+release_status = "Development Status :: 5 - Production/Stable"
 dependencies = ["google-api-core[grpc] >= 1.14.0, < 2.0.0dev"]
 extras = {"pandas": "pandas >= 0.17.1"}