Move go version to dedicated `.go-version` file

[MrDXY]

Motivation:

Introduce a .go-version file to make it easier to maintain go versions among multiple files that use it.

Changes Made:

• Added a .go-version file to the root directory of the project.
  • The .go-version file contains the desired Go version (e.g., go1.22.2) required for this project.
• Updated the project's related workflow files.
  • .github/workflows/govuln.yaml
  • .github/workflows/static-analysis.yaml
  • .github/workflows/test_amd64.yaml
  • .github/workflows/test_template.yaml

Reference: https://github.com/etcd-io/raft/pull/191#issuecomment-2037314440