Make version a major minor patch

[CasperWA]

Use major version 2 to show that this is a new run of packages releases named httpx2-auth that is different from httpx-auth.

AI Summary

This pull request primarily updates the versioning for the httpx2_auth package, rolling back the version from 2.0.1.0 to 2.0.0 and making related adjustments across the codebase and CI/CD workflows. Additionally, it removes the badges section from the README.md.

Versioning and packaging updates:

• Set the __version__ in httpx2_auth/__init__.py to "2.0.0" and updated the versioning note.
• Updated the installation commands in .github/workflows/ci_tests.yml to use the 2.0.0 wheel and source distribution instead of 2.0.1.0.
• Adjusted the version-matching regex in .github/workflows/cd_release.yml to match any version, not just 2.x.x.x, for release automation.

Documentation:

• Removed the badges section (PyPI version, build status, coverage, code style, test count, downloads) from the top of README.md for a cleaner appearance.

[Copilot]

Pull request overview

Switches the package version scheme from a four-segment 2.0.1.0 to standard semver 2.0.0, updates CI/CD references accordingly, and removes the badges block from the README.

Changes:

• Set __version__ to "2.0.0" and update the accompanying comment.
• Update ci_tests.yml wheel/sdist filenames and cd_release.yml regex to match three-segment versions.
• Remove badges section from README.md.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
httpx2_auth/__init__.py	Version rolled back to 2.0.0 with updated note.
.github/workflows/ci_tests.yml	Install commands reference the new 2.0.0 artifact filenames.
.github/workflows/cd_release.yml	Regex broadened to match three-segment versions for future bumps.
README.md	Removed badges block.

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[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@ebfc179). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
httpx2_auth/__init__.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main       #3   +/-   ##
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  Coverage        ?   71.31%           
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  Files           ?       14           
  Lines           ?      917           
  Branches        ?        0           
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  Hits            ?      654           
  Misses          ?      263           
  Partials        ?        0           

Flag	Coverage Δ
local	71.31% <0.00%> (?)

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