Update SECURITY.md

[colin-gourlay]

Corrected typo

Description:

Related issue (if applicable): #

Checklist

• [x] The code change is tested and works locally.
• [x] There is no commented out code in this PR.
• [x] No lint errors (use flake8)
• [x] 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/caronc/apprise.git@<this.branch-name>

# Test out the changes with the following command:
apprise -t "Test Title" -b "Test Message" \
  <apprise url related to ticket>

[codecov-commenter]

Codecov Report

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

Comparison is base (f1d697f) 99.51% compared to head (6793a82) 99.51%.

:exclamation: Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1002 +/- ## ======================================= Coverage 99.51% 99.51% ======================================= Files 125 125 Lines 16760 16760 Branches 3434 3434 ======================================= Hits 16679 16679 Misses 70 70 Partials 11 11 ```

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

[caronc]

Thank you for this :slightly_smiling_face: