feat: Add support for latest MSTeams webhook URL format

[anothermwilson]

Description:

Related issue (if applicable): #1227

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• No lint errors (use flake8)
• 100% test coverage

Testing

Anyone can help test this source code as follows:

# Create a virtual environment to work in as follows:
python3 -m venv apprise

# Change into our new directory
cd apprise

# Activate our virtual environment
source bin/activate

# Install the branch
pip install git+https://github.com/anothermwilson/apprise.git@MW-1127-support-msteams-new-webhook-url

# Test out the changes with the following command:
apprise -t "Test MSTeams Latest Webhook URL Format" -b "Test Message" \
  https://yourteam.webhook.office.com/webhookb2/{token_a}/IncomingWebhook/{token_b}/{token_c}/{token_d}

[anothermwilson]

This pattern could be relaxed - I have just observed that any new webhook URLs have a token here that starts with V2

[anothermwilson]

the token can contain dashes and underscores

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.37%. Comparing base (4d21759) to head (6ad013b).
Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1253   +/-   ##
=======================================
  Coverage   99.37%   99.37%           
=======================================
  Files         148      148           
  Lines       20776    20796   +20     
  Branches     3709     3717    +8     
=======================================
+ Hits        20646    20666   +20     
  Misses        121      121           
  Partials        9        9           

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[caronc]

This looks great; it appears to be very backwards compatible too! Great job! 🚀