[minor] Set header

[ssunorz]

Description

I used this as a reference. https://github.com/golang/oauth2/blob/master/transport.go

Type of change

• [ ] Bug fix
• [x] New feature
• [ ] Refactoring (no functional changes, no api changes)
• [ ] Non-code changes (update documentation, pipeline, etc.)

Flags

• [ ] breaks backward compatibility
• [x] requires a documentation update
• [ ] has untestable code

Related issue/PR

Delete if not applicable

• Fixes #issue
• Closes #PR

---

Checklist

• [x] Followed the guidelines in the CONTRIBUTING document
• [x] Added prefix [major]/[minor]/[patch]/[skip] in the PR title
• [x] Tested and linted the code
• [x] Commented the code
• [x] Made corresponding changes to the documentation
• [x] Confirmed no dropping in test coverage (by Codecov)
• [x] Passed all pipeline checking
• [x] Approved by >1 reviewer

Checklist for maintainer

• [x] Use Squash and merge
• [x] Double-confirm the merge message has prefix [major]/[minor]/[patch]/[skip]
• [x] Delete the branch after merge

[codecov-commenter]

Codecov Report

Merging #66 into master will decrease coverage by 0.86%. The diff coverage is 75.51%.

@@            Coverage Diff             @@
##           master      #66      +/-   ##
==========================================
- Coverage   87.66%   86.80%   -0.87%     
==========================================
  Files          14       15       +1     
  Lines         689      735      +46     
==========================================
+ Hits          604      638      +34     
- Misses         75       87      +12     
  Partials       10       10              

Impacted Files	Coverage Δ
service/authorizerd_mock.go	0.00% <0.00%> (ø)
handler/principal_mock.go	100.00% <100.00%> (ø)
handler/transport.go	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update a6694f7...93d1112. Read the comment docs.