feat: add custom default HTTP headers support

[alespour]

With #31 merged-in

• Closes #25
• Closes #26

Proposed Changes

Adds custom (default) HTTP headers support.

Checklist

• [x] CHANGELOG.md updated
• [x] Rebased/mergeable
• [x] A test has been added if appropriate
• [x] Tests pass
• [x] Commit messages are conventional

[codecov[bot]]

Codecov Report

Merging #30 (27429d2) into main (0dad3dd) will increase coverage by 2.76%. The diff coverage is 78.36%.

@@            Coverage Diff             @@
##             main      #30      +/-   ##
==========================================
+ Coverage   78.59%   81.35%   +2.76%     
==========================================
  Files           8        9       +1     
  Lines         528      574      +46     
==========================================
+ Hits          415      467      +52     
+ Misses         97       93       -4     
+ Partials       16       14       -2     

Files Changed	Coverage Δ
influxdb3/point.go	100.00% <ø> (ø)
influxdb3/reflection.go	50.00% <ø> (ø)
influxdb3/query_iterator.go	43.26% <43.26%> (ø)
influxdb3/query.go	81.81% <81.81%> (ø)
influxdb3/write.go	97.56% <97.56%> (ø)
influxdb3/client.go	91.58% <100.00%> (ø)
influxdb3/error.go	100.00% <100.00%> (ø)
influxdb3/fix_url.go	100.00% <100.00%> (ø)
influxdb3/query_type.go	100.00% <100.00%> (ø)