[PMSH] Fixes for Flask, MarkupSafe versions + tox

Fixes due to version issues and minor fixes for tox and unit test
Patch 3+4: Version bump

Issue-ID: DCAEGEN2-3086

Signed-off-by: egernug <gerard.nugent@est.tech>
Change-Id: Ibbb83bb50f96737ad127c4c2463957500f7581db
8 files changed