docs(spanner): backfill missing release notes for v6.113.0 to v6.116.1

Backfills release notes for Spanner versions that were released on Maven Central but missing from the monorepo changelog:
- v6.113.0
- v6.114.0
- v6.115.0
- v6.116.0
- v6.116.1
Generated using the custom release note generator script with pom.xml fallback.

Author: meltsufin

java-spanner/CHANGELOG.md

@@ -1,5 +1,50 @@
 # Changelog
 
+## [6.116.1](https://github.com/googleapis/google-cloud-java/compare/1b0a9a014fd...cd6048171fc) (2026-04-21)
+
+### Features
+
+* feat(spanner): add shared endpoint cooldowns for location-aware rerouting (#12845) ([f5f273b](https://github.com/googleapis/google-cloud-java/commit/f5f273ba0bd6b7ca9a8be7d1b5a89211ef5ff9fc))
+
+
+## [6.116.0](https://github.com/googleapis/google-cloud-java/compare/6bef068b4d8...1b0a9a014fd) (2026-04-14)
+
+
+## [6.115.0](https://github.com/googleapis/google-cloud-java/compare/c2147fc9ab7...5c303706d40) (2026-04-13)
+
+### Bug Fixes
+
+* fix(java-spanner): use the existing dependency versions (#12746) ([8650bc6](https://github.com/googleapis/google-cloud-java/commit/8650bc6d907a5ad25f191a3d83d993d6d069694e))
+* fix(spanner): preserve all async cache updates (#12740) ([b8bf432](https://github.com/googleapis/google-cloud-java/commit/b8bf432f48f48bb454ba0ea50e40bfabca0ebc24))
+* fix(spanner):  fix grpc-gcp affinity cleanup and multiplexed channel usage leaks (#12726) ([55c9857](https://github.com/googleapis/google-cloud-java/commit/55c985776700b1219ece39a519021030eb18d927))
+* fix(spanner): ensure executeQueryAsync is non-blocking (#12715) ([b7e34d2](https://github.com/googleapis/google-cloud-java/commit/b7e34d22191df6bf7fc2aa30bd83234312dd89c6))
+* fix(spanner): honor built-in metrics opt-out for gRPC metrics exporter (#12711) ([57baaea](https://github.com/googleapis/google-cloud-java/commit/57baaeaae5ef1f819e04b253dfcf570499ccc110))
+
+
+## [6.114.0](https://github.com/googleapis/google-cloud-java/compare/a35f1c267d8...4042feed629) (2026-04-10)
+
+### Bug Fixes
+
+* fix(java-spanner): use the existing dependency versions (#12746) ([8650bc6](https://github.com/googleapis/google-cloud-java/commit/8650bc6d907a5ad25f191a3d83d993d6d069694e))
+* fix(spanner): preserve all async cache updates (#12740) ([b8bf432](https://github.com/googleapis/google-cloud-java/commit/b8bf432f48f48bb454ba0ea50e40bfabca0ebc24))
+* fix(spanner):  fix grpc-gcp affinity cleanup and multiplexed channel usage leaks (#12726) ([55c9857](https://github.com/googleapis/google-cloud-java/commit/55c985776700b1219ece39a519021030eb18d927))
+* fix(spanner): ensure executeQueryAsync is non-blocking (#12715) ([b7e34d2](https://github.com/googleapis/google-cloud-java/commit/b7e34d22191df6bf7fc2aa30bd83234312dd89c6))
+* fix(spanner): honor built-in metrics opt-out for gRPC metrics exporter (#12711) ([57baaea](https://github.com/googleapis/google-cloud-java/commit/57baaeaae5ef1f819e04b253dfcf570499ccc110))
+* fix: update Version.java and correct spanner version for 1.83.0 release (#12712) ([c2147fc](https://github.com/googleapis/google-cloud-java/commit/c2147fc9ab767b0546e6f71483e3f0af1a99740c))
+
+
+## [6.113.0](https://github.com/googleapis/google-cloud-java/compare/8e13cf00a16...c2147fc9ab7~1) (2026-04-08)
+
+### Features
+
+* feat: Switch Eef metrics to using built in open telemetry (#4385) ([759bb22](https://github.com/googleapis/google-cloud-java/commit/759bb22da811ac9cdb6f8720a3e22e0b17c8f4e9))
+
+### Bug Fixes
+
+* fix(spanner): enforce READY-only location aware routing and add endpoint lifecycle management ([ecb86fd](https://github.com/googleapis/google-cloud-java/commit/ecb86fd8be5fd6e2d470434d5a7b74afb96220d0))
+* fix(spanner): improve grpc-gcp affinity cleanup and location-aware retries ([a157c2f](https://github.com/googleapis/google-cloud-java/commit/a157c2f09e431bc61dd74b375bfb2dcf812d81f4))
+
+
 ## [6.112.0](https://github.com/googleapis/java-spanner/compare/v6.111.1...v6.112.0) (2026-03-17)
 
 
@@ -3704,4 +3749,4 @@ Apologies for the inconvenience.
 
 ### Dependencies
 
-* update dependency org.jacoco:jacoco-maven-plugin to v0.8.5 ([#7023](https://www.github.com/googleapis/java-spanner/issues/7023)) ([d8b6438](https://www.github.com/googleapis/java-spanner/commit/d8b6438aa3b881c1c9baff584a74813664be4df8))
+* update dependency org.jacoco:jacoco-maven-plugin to v0.8.5 ([#7023](https://www.github.com/googleapis/java-spanner/issues/7023)) ([d8b6438](https://www.github.com/googleapis/java-spanner/commit/d8b6438aa3b881c1c9baff584a74813664be4df8))