Update dependency flask to v0.12.3 [SECURITY]

Author: renovate[bot]

_RESOURCES/course-work/Sprint-Challenge--Hash-BC-andrew-brudnak/Pipfile

@@ -8,7 +8,7 @@ flake8 = "*"
 
 [packages]
 requests = "==2.18.4"
-flask = "==0.12.2"
+flask = "==0.12.3"
 
 [requires]
 python_version = "3.7"