[LLVM Utils] Update Certifi to 2023.5.7

Certifi 2022.12.07 removes root certificates from "TrustCor" from the
root store. These are in the process of being removed from Mozilla's
trust store.

https://groups.google.com/a/mozilla.org/g/dev-security-policy/c/oxX69KFvsm4/m/yLohoVqtCgAJ

llvm/utils/git/requirements.txt

@@ -4,7 +4,7 @@
 #
 #    pip-compile --output-file=requirements.txt requirements.txt.in
 #
-certifi==2022.9.24
+certifi==2023.5.7
     # via requests
 cffi==1.15.1
     # via pynacl