standardize header to bytes

[nggit]

Before:

REMOTE_ADDR:    b'127.0.0.1'
HTTP_HOST:      bytearray(b'localhost:8000')
REQUEST_METHOD: bytearray(b'GET')
REQUEST_SCHEME: b'http'
REQUEST_URI:    bytearray(b'/hello?a=1&b=2')
PATH:           bytearray(b'/hello')
QUERY:          {'a': ['1'], 'b': ['2']}
QUERY_STRING:   bytearray(b'a=1&b=2')
VERSION:        b'1.1'

After:

REMOTE_ADDR:    b'127.0.0.1'
HTTP_HOST:      b'localhost:8000'
REQUEST_METHOD: b'GET'
REQUEST_SCHEME: b'http'
REQUEST_URI:    b'/hello?a=1&b=2'
PATH:           b'/hello'
QUERY:          {'a': ['1'], 'b': ['2']}
QUERY_STRING:   b'a=1&b=2'
VERSION:        b'1.1'

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 91.78%. Comparing base (07c01b7) to head (805efd3). Report is 1 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #95 +/- ## ========================================== - Coverage 91.78% 91.78% -0.01% ========================================== Files 24 24 Lines 2264 2263 -1 ========================================== - Hits 2078 2077 -1 Misses 186 186 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[sonarcloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud