No provider versions constraint for GCP and Aliyun and need to support values file customization for tidb-operator and tidb-cluster

[DanielZhangQD]

Bug Report

What version of Kubernetes are you using?

1.12.8
What version of TiDB Operator are you using?

v1.0.1
What storage classes exist in the Kubernetes cluster and what are used for PD/TiKV pods?

pd-ssd
What's the status of the TiDB cluster pods?

Running
What did you do?

Run terraform init
What did you expect to see?
No prompt for version constraint
What did you see instead?
Output from terraform init:
To prevent automatic upgrades to new major versions that may contain breaking
changes, it is recommended to add version = "..." constraints to the
corresponding provider blocks in configuration, with the constraint strings
suggested below.

• provider.alicloud: version = "~> 1.56"
• provider.external: version = "~> 1.2"
• provider.helm: version = "~> 0.10"
• provider.null: version = "~> 2.1"
• provider.template: version = "~> 2.1"