Move some core pypi deps into requirements file

docker/Dockerfile

@@ -77,10 +77,7 @@ RUN apk add --no-cache postgresql postgresql-contrib postgresql-dev libpq
 RUN apk add --no-cache mariadb-connector-c mariadb-dev mariadb-client
 
 # Install required python packages
-RUN pip install --upgrade pip setuptools wheel
-RUN pip install --no-cache-dir -U invoke
 RUN pip install --no-cache-dir -U psycopg2 mysqlclient pgcli mariadb
-RUN pip install --no-cache-dir -U gunicorn
 
 FROM base as production
 # Clone source code

requirements.txt

@@ -1,6 +1,12 @@
+# Basic package requirements
+setuptools>=57.4.0
+wheel>=0.37.0
 invoke>=1.4.0                   # Invoke build tool
-wheel>=0.34.2                   # Wheel
+gunicorn>=20.1.0                # Gunicorn web server
+
+# Django framework
 Django==3.2.4                     # Django package
+
 pillow==8.2.0                   # Image manipulation
 djangorestframework==3.12.4     # DRF framework
 django-cors-headers==3.2.0      # CORS headers extension for DRF
@@ -33,7 +39,6 @@ django-test-migrations==1.1.0   # Unit testing for database migrations
 python-barcode[images]==0.13.1  # Barcode generator
 qrcode[pil]==6.1                # QR code generator
 django-q==1.3.4                 # Background task scheduling
-gunicorn>=20.0.4                # Gunicorn web server
 django-formtools==2.3           # Form wizard tools
 
 inventree                       # Install the latest version of the InvenTree API python library