[dev] Remove gitpod

[rickyyx]

Signed-off-by: rickyyx [email protected]

Why are these changes needed?

Reverting changes from https://github.com/ray-project/ray/pull/15420 so that we no longer need to update the Dockerfile here with python upgrade and dependency changes.

Related issue number

Checks

• [ ] I've signed off every commit(by using the -s flag, i.e., git commit -s) in this PR.
• [ ] I've run scripts/format.sh to lint the changes in this PR.
• [ ] I've included any doc changes needed for https://docs.ray.io/en/master/.
• [ ] I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/
• Testing Strategy
  • [ ] Unit tests
  • [ ] Release tests
  • [ ] This PR is not tested :(