Bump pyodbc from 4.0.27 to 4.0.28 in /base (#77)

Bumps [pyodbc](https://github.com/mkleehammer/pyodbc) from 4.0.27 to 4.0.28.
- [Release notes](https://github.com/mkleehammer/pyodbc/releases)
- [Commits](mkleehammer/pyodbc@4.0.27...4.0.28)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

base/requirements.txt

@@ -3,4 +3,4 @@ brotlipy==0.7.0
 cchardet==2.1.5
 mysqlclient==1.4.6
 psycopg2==2.8.4
-pyodbc==4.0.27
+pyodbc==4.0.28