[maven-release-plugin] copy for tag java-function-invoker-parent-1.0.…

…0-alpha-2-rc4

[maven-release-plugin] copy for tag java-function-invoker-parent-1.0.…

…0-alpha-2-rc3

[maven-release-plugin] copy for tag java-function-invoker-parent-1.0.…

…0-alpha-2-rc2

[maven-release-plugin] copy for tag java-function-invoker-parent-1.0.…

…0-alpha-2-rc1

[maven-release-plugin] copy for tag functions-framework-api-1.0.0-alp…

…ha-2-rc3

[maven-release-plugin] copy for tag functions-framework-api-1.0.0-alp…

…ha-2-rc2

[maven-release-plugin] copy for tag functions-framework-api-1.0.0-alp…

…ha-2-rc1

Change groupId to com.google.cloud.functions. (GoogleCloudPlatform#2)