Align % formatting in Cursor.executemany() with Cursor.execute()

[Nothing4You]

What do these changes do?

port the changes from PyMySQL/PyMySQL#450

Are there changes in behavior for the user?

%% is now required for literal % in Cursor.executemany().
This aligns behavior with Cursor.execute().

Related issue number

closes #545

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes
• Add a new news fragment to CHANGES.txt

[codecov]

Codecov Report

Merging #721 (b7856cf) into master (2aef3c7) will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #721      +/-   ##
==========================================
- Coverage   92.69%   92.69%   -0.01%     
==========================================
  Files          35       35              
  Lines        5434     5432       -2     
  Branches      586      586              
==========================================
- Hits         5037     5035       -2     
  Misses        309      309              
  Partials       88       88              

Flag	Coverage Δ
ubuntu-latest_3.10_mariadb-10.2	89.48% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.10_mariadb-10.3	89.48% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.10_mariadb-10.4	89.48% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.10_mariadb-10.5	89.46% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.10_mariadb-10.6	89.46% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.10_mariadb-10.7	89.46% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.10_mysql-5.7	90.18% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.10_mysql-8.0	91.60% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.7_mariadb-10.2	88.89% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.7_mariadb-10.3	88.89% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.7_mariadb-10.4	88.89% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.7_mariadb-10.5	88.88% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.7_mariadb-10.6	88.88% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.7_mariadb-10.7	88.88% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.7_mysql-5.7	89.64% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.7_mysql-8.0	91.14% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.8_mariadb-10.2	89.52% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.8_mariadb-10.3	89.52% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.8_mariadb-10.4	89.52% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.8_mariadb-10.5	89.51% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.8_mariadb-10.6	89.51% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.8_mariadb-10.7	89.51% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.8_mysql-5.7	90.23% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.8_mysql-8.0	91.63% <100.00%> (+0.01%)	⬆️
ubuntu-latest_3.9_mariadb-10.2	89.40% <100.00%> (-0.01%)	⬇️
ubuntu-latest_3.9_mariadb-10.3	89.40% <100.00%> (-0.01%)	⬇️
ubuntu-latest_3.9_mariadb-10.4	89.40% <100.00%> (-0.01%)	⬇️
ubuntu-latest_3.9_mariadb-10.5	89.38% <100.00%> (-0.01%)	⬇️
ubuntu-latest_3.9_mariadb-10.6	89.38% <100.00%> (-0.01%)	⬇️
ubuntu-latest_3.9_mariadb-10.7	89.38% <100.00%> (-0.01%)	⬇️
ubuntu-latest_3.9_mysql-5.7	90.10% <100.00%> (-0.01%)	⬇️
ubuntu-latest_3.9_mysql-8.0	91.50% <100.00%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
aiomysql/cursors.py	92.55% <100.00%> (ø)
tests/test_cursor.py	100.00% <100.00%> (ø)

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