Release with Error Prone 2.3.5-SNAPSHOT

This release includes demotion of several breaking checks from ERROR to WARN severity: [1].

Baseline is this EP commit: [2] and this Bazel commit: [3].

[1] google/error-prone#1620
[2] google/error-prone@8beaab4
[3] bazelbuild/bazel@bc74d1d