chore: update gapic-generator-java version to 2.1.0 (#522)
chore: update gapic-generator-java version to 2.1.0 (#522)

PiperOrigin-RevId: 391407209

Source-Author: Google APIs <1505422b2465e9a84f6fdfaa161078890c593f06@google.com>
Source-Date: Tue Aug 17 16:48:10 2021 -0700
Source-Repo: googleapis/googleapis
Source-Sha: e1738ee972b49fd0c4d4718b035444495142b781
Source-Link: https://github.com/googleapis/googleapis/commit/e1738ee972b49fd0c4d4718b035444495142b781

Co-authored-by: Emily Ball <9fe61a4aacf035e9f06745e509f03712e2d9e90e@google.com>
googleapis/java-websecurityscanner,googleapis/java-websecurityscanner,googleapis/java-websecurityscanner