Add support for OTEL_SERVICE_NAME

[owais]

Description

Adds support for OTEL_SERVICE_NAME environment variable and updated otel dep to 1.2.0

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• Tested manually
• Added automated tests

Checklist:

• Changelogs have been updated
• Unit tests have been added/updated
• Documentation has been updated

[codecov]

Codecov Report

Merging #64 (fdda834) into main (8fcdd94) will increase coverage by 0.32%.
The diff coverage is 85.71%.

❗ Current head fdda834 differs from pull request most recent head 0e82de3. Consider uploading reports for the commit 0e82de3 to get more accurate results

@@            Coverage Diff             @@
##             main      #64      +/-   ##
==========================================
+ Coverage   63.87%   64.19%   +0.32%     
==========================================
  Files           7        7              
  Lines         155      162       +7     
  Branches       22       21       -1     
==========================================
+ Hits           99      104       +5     
- Misses         49       50       +1     
- Partials        7        8       +1     

Impacted Files	Coverage Δ
splunk_otel/tracing.py	53.57% <50.00%> (-0.82%)	⬇️
splunk_otel/options.py	80.59% <89.47%> (-0.76%)	⬇️

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[pellared]

This can be moved to ### Deprecated section.
Reference: https://keepachangelog.com/en/1.1.0/

[owais]

Done. Thanks.