chore: release 1.18.0

[release-please]

🤖 I have created a release *beep* *boop*

1.18.0 (2021-04-09)

Features

• add deprecated annotation and tag to bq storage alpha api (#978) (c7da342)
• re-generated to pick up changes from googleapis. (#982) (17bfbd8)

Bug Fixes

• Cleanup JsonWriter bytes conversion code and add some test coverage (#984) (e43df34)

Documentation

• update region tag for the storage quickstart (#985) (1d0d6c3)

Dependencies

• update dependency com.google.cloud:google-cloud-bigquery to v1.127.12 (#986) (d39bd79)
• update dependency com.google.cloud:google-cloud-shared-dependencies to v0.21.0 (#987) (4fa3dbb)

---

This PR was generated with Release Please. See documentation.

[codecov]

Codecov Report

Merging #981 (d5f5b45) into master (4fa3dbb) will increase coverage by 0.05%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #981      +/-   ##
============================================
+ Coverage     81.10%   81.15%   +0.05%     
  Complexity     1046     1046              
============================================
  Files            78       78              
  Lines          5668     5668              
  Branches        435      435              
============================================
+ Hits           4597     4600       +3     
+ Misses          884      881       -3     
  Partials        187      187              

Impacted Files	Coverage Δ	Complexity Δ
...e/cloud/bigquery/storage/v1beta2/StreamWriter.java	83.94% <0.00%> (+0.68%)	33.00% <0.00%> (ø%)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 4fa3dbb...d5f5b45. Read the comment docs.

[yoshi-automation]

🤖 Release is at https://github.com/googleapis/java-bigquerystorage/releases/tag/v1.18.0 🌻

[release-tool-publish-reporter]

The release build has started, the log can be viewed here. 🌻

[release-tool-publish-reporter]

🥚 You hatched a release! The release build finished successfully! 💜