"drf-yasg" missing in Image for Netbox v2.6.6 and v2.6

[fdebonneval]

Current Behavior

Netbox Worker image crashes on start with message :
ModuleNotFoundError: No module named 'drf_yasg'

...

Expected Behavior

Netbox Worker image should start without error
...

Debug Information

The output of docker-compose logs netbox:

# docker logs 2c6f1f4747d4
Traceback (most recent call last):
  File "/opt/netbox/netbox/manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python3.7/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.7/site-packages/django/core/management/__init__.py", line 357, in execute
    django.setup()
  File "/usr/local/lib/python3.7/site-packages/django/__init__.py", line 24, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/usr/local/lib/python3.7/site-packages/django/apps/registry.py", line 91, in populate
    app_config = AppConfig.create(entry)
  File "/usr/local/lib/python3.7/site-packages/django/apps/config.py", line 90, in create
    module = import_module(entry)
  File "/usr/local/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 965, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'drf_yasg'

The output of pip3 list in the Netbox Application image :

bash-5.0# pip3 list
Package                  Version
------------------------ ---------
certifi                  2019.9.11
cffi                     1.13.0
chardet                  3.0.4
ciscoconfparse           1.4.7
Click                    7.0
colorama                 0.4.1
coreapi                  2.3.3
coreschema               0.0.4
Django                   2.2.6
django-auth-ldap         2.0.0
django-cacheops          4.1
django-cors-headers      3.0.2
django-debug-toolbar     2.0
django-filter            2.1.0
django-js-asset          1.2.2
django-mptt              0.9.1
django-prometheus        1.0.15
django-rq                2.1.0
django-tables2           2.0.6
django-taggit            1.1.0
django-taggit-serializer 0.1.7
django-timezone-field    3.0
djangorestframework      3.9.4
dnspython                1.16.0
eventlet                 0.25.1
funcy                    1.13
future                   0.18.1
graphviz                 0.10.1
greenlet                 0.4.15
gunicorn                 19.9.0
idna                     2.8
inflection               0.3.1
itypes                   1.1.0
Jinja2                   2.10.3
junos-eznc               2.2.1
lxml                     4.4.1
Markdown                 2.6.11
MarkupSafe               1.1.1
monotonic                1.5
more-itertools           7.2.0
napalm                   2.5.0
ncclient                 0.6.6
netaddr                  0.7.19
netmiko                  2.4.2
nxapi-plumbing           0.5.2
paramiko                 2.6.0
passlib                  1.7.1
Pillow                   6.0.0
pip                      19.3.1
prometheus-client        0.7.1
psycopg2-binary          2.8.3
py-gfm                   0.1.4
pyasn1                   0.4.7
pyasn1-modules           0.2.7
pycparser                2.19
pycryptodome             3.8.2
pyeapi                   0.8.2
pyIOSXR                  0.53
pyrsistent               0.15.4
pyserial                 3.4
python-ldap              3.2.0
pytz                     2019.3
PyYAML                   5.1.2
redis                    3.3.11
requests                 2.22.0
rq                       1.1.0
ruamel.yaml              0.16.5
ruamel.yaml.clib         0.2.0
scp                      0.13.2
setuptools               41.4.0
six                      1.12.0
sqlparse                 0.3.0
swagger-spec-validator   2.4.3
textfsm                  0.4.1
uritemplate              3.0.0
urllib3                  1.25.6
wheel                    0.33.6

[sdktr]

Jinja2 misses as well; a docker build based on 0.18.2 release of this repo works correctly