Ignore generated DevelocityApi (#171)

Like the generated `GradleEnterpriseApi` class, this just duplicates all
methods from `BuildsApi` and others.

Cherry-pick of #170.

Author: gabrielfeo

library/.openapi-generator-ignore

@@ -6,4 +6,5 @@ build/generated/openapi-generator/docs/*
 build/generated/openapi-generator/src/main/AndroidManifest.xml
 build/generated/openapi-generator/src/main/kotlin/com/gabrielfeo/gradle/enterprise/api/internal/infrastructure/ApiClient.kt
 build/generated/openapi-generator/src/main/kotlin/com/gabrielfeo/gradle/enterprise/api/GradleEnterpriseApi.kt
+build/generated/openapi-generator/src/main/kotlin/com/gabrielfeo/gradle/enterprise/api/DevelocityApi.kt
 build/generated/openapi-generator/src/test/**/*