Bump mysqlclient from 2.2.0 to 2.2.4

2.2.0 wasn't building for me on OSX with the latest MySQL client libraries. 2.2.4 builds fine.

requirements.txt

@@ -33,7 +33,7 @@ pangres==4.2.1
 
 SQLAlchemy==2.0.23
 psycopg==3.1.12
-mysqlclient==2.2.0
+mysqlclient==2.2.4
 google-cloud-bigquery[pandas]==3.13.0
 
 debugpy==1.8.0
@@ -42,4 +42,4 @@ pinax-eventlog==5.1.1  #no updates
 pycryptodome==3.19.1
 PyLTI1p3==2.0.0 #no further update Nov 2022)
 hjson==3.1.0
-pytz==2023.3.post1
+pytz==2023.3.post1