Move rustfmt to stable check

Dependencies

• [2] OFRX6SW6 Fix Pipelines
• [3] HEGER5WD Add Pipelines

Change contents

• edit in bitbucket-pipelines.yml at line 21
  [3.703]

  [3.703]
  + - rustup component add rustfmt-preview

  + - cargo fmt -- --version

  + - cargo fmt --all -- --check
• edit in bitbucket-pipelines.yml at line 32
  [3.919]→[3.919:988](∅→∅)
  − - rustup component add rustfmt-preview --toolchain nightly
• edit in bitbucket-pipelines.yml at line 38
  [2.62]→[3.1247:1321](∅→∅),[3.1247]→[3.1247:1321](∅→∅)
  − - cargo fmt -- --version

  − - cargo fmt --all -- --check