Downgrading PyYAML to 5.3.1 due to 5.4 failing to build for Cython<3

Solution taken from yaml/pyyaml#724
Main issue yaml/pyyaml#728
Recommended workaround yaml/pyyaml#736

Author: said-moj

requirements/generated/requirements-dev.txt

@@ -239,7 +239,7 @@ pytz==2021.1
     #   -r requirements/source/requirements-base.in
     #   celery
     #   cla-common
-pyyaml==5.4
+pyyaml==5.3.1
     # via
     #   -r requirements/source/requirements-base.in
     #   aspy.yaml

requirements/generated/requirements-docs.txt

@@ -181,7 +181,7 @@ pytz==2021.1
     #   babel
     #   celery
     #   cla-common
-pyyaml==5.4
+pyyaml==5.3.1
     # via -r requirements/source/requirements-base.in
 requests==2.27.1
     # via

requirements/generated/requirements-production.txt

@@ -160,7 +160,7 @@ pytz==2021.1
     #   -r requirements/source/requirements-base.in
     #   celery
     #   cla-common
-pyyaml==5.4
+pyyaml==5.3.1
     # via -r requirements/source/requirements-base.in
 requests==2.27.1
     # via

requirements/generated/requirements-testing.txt

@@ -202,7 +202,7 @@ pytz==2021.1
     #   -r requirements/source/requirements-base.in
     #   celery
     #   cla-common
-pyyaml==5.4
+pyyaml==5.3.1
     # via -r requirements/source/requirements-base.in
 requests==2.27.1
     # via

requirements/source/requirements-base.in

@@ -41,7 +41,7 @@ polib==1.0.6
 # Fork PgFulltext - PR added
 https://github.com/ministryofjustice/djorm-ext-pgfulltext/archive/refs/tags/0.1.0.tar.gz
 celery==4.0.2
-PyYAML==5.4
+PyYAML==5.3.1
 pyminizip==0.2.3
 
 #Irat healthcheck and ping package