Disconnect from spring-cloud-dependencies-parent

[elefeint]

spring-cloud-gcp-dependencies still lists spring-cloud-dependencies-parent as its parent. This is a relic from the time when this project was under spring-cloud organization.

There are a couple of things that need to be done:

1. Remove the <parent> section in the spring-cloud-gcp-dependencies pom.xml. Note that it will no longer have any parent. This is normal (here is libraries BOM as an example).
2. Look through the spring-cloud-dependencies-parent sections that used to be inherited, and add the correct equivalent to spring-cloud-gcp-dependencies BOM. For example, the license needs to be added (use spring-cloud-gcp root poml.xml and just copy what it has). We don't need any of the profiles; our build does not use these.