build(deps): bump com.google.devtools.ksp:symbol-processing-api

Bumps [com.google.devtools.ksp:symbol-processing-api](https://github.com/google/ksp) from 1.9.10-1.0.13 to 2.0.0-1.0.21.
- [Release notes](https://github.com/google/ksp/releases)
- [Commits](google/ksp@1.9.10-1.0.13...2.0.0-1.0.21)

---
updated-dependencies:
- dependency-name: com.google.devtools.ksp:symbol-processing-api
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

core/kotlin/bestbefore-processor-kotlin/build.gradle

@@ -6,7 +6,7 @@ plugins {
 apply from: "${rootDir}/gradle/publish.gradle"
 
 dependencies {
-    implementation 'com.google.devtools.ksp:symbol-processing-api:1.9.10-1.0.13'
+    implementation 'com.google.devtools.ksp:symbol-processing-api:2.0.0-1.0.21'
     implementation 'com.google.auto.service:auto-service-annotations:1.1.1'
     ksp 'dev.zacsweers.autoservice:auto-service-ksp:1.1.0'
 }