Updates for analyzer 8, prepare for release. (#832)

Reland ad1fdf0:

Migrate from deprecated analyzer APIs.

PiperOrigin-RevId: 795720488

Reland b9e352e:

Stop using deprecated AST properties.

PiperOrigin-RevId: 794217404

Reland b491d59.

Update test for upcoming Analyzer change

PiperOrigin-RevId: 786680884

Co-authored-by: Googler <copybara-servicebot@google.com>

Author: davidmorgan

CHANGELOG.md

@@ -1,6 +1,8 @@
 ## 5.5.1
 
-* Allow `source_gen: ">=3.0.0 <5.0.0"`.
+* Require `analyzer: ^8.1.0`.
+* Allow `source_gen: '>=3.0.0 <5.0.0'`.
+* Allow `build: '>=3.0.0 <5.0.0'`.
 
 ## 5.5.0