chore(main): release 1.21.0

[release-please]

🤖 I have created a release beep boop

1.21.0 (2024-05-01)

Features

• Update parser to handle RENAME and SYNONYM (#101) (49a08fd)

Bug Fixes

• Compilation issues with error-prone on JDK16+ (#100) (7e98200)
• deps: bump com.google.errorprone:error_prone_core (#99) (b51fa4c)
• deps: Bump com.google.errorprone:error_prone_core from 2.25.0 to 2.26.1 (#93) (1c1cb59)
• deps: Bump com.google.guava:guava from 33.0.0-jre to 33.1.0-jre (#92) (1dd2837)
• deps: bump commons-cli:commons-cli from 1.6.0 to 1.7.0 (#98) (e9a3514)
• deps: Bump org.apache.maven.plugins:maven-compiler-plugin (#95) (226e5a2)
• deps: Bump slf4j.version from 2.0.12 to 2.0.13 (#96) (e4b0471)
• Update dependabot.yml to add conventional commit prefix (f0a4cb7)
• Update dependabot.yml to add conventional commit prefix (97243fa)

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[release-please]

🤖 Release is at https://github.com/cloudspannerecosystem/spanner-schema-diff-tool/releases/tag/v1.21.0 🌻