Update dependency dulwich to v0.22.7

Author: renovate[bot]

requirements-container.txt

@@ -1,5 +1,5 @@
 django-auth-ldap==5.1.0
 django-storages[azure,boto3,dropbox,google,libcloud,sftp]==1.14.4
-dulwich==0.22.6
+dulwich==0.22.7
 python3-saml==1.16.0 --no-binary lxml,xmlsec
 sentry-sdk[django]==2.19.2