Fix pip requirements

pilow version upgraded and django-phonenumber-field version downgraded so there are no conflicts in required dependency versions

.gitlab-ci.yml

@@ -13,8 +13,8 @@ variables:
   stage: test
   before_script:
     - apt-get update && apt-get install -y --allow-unauthenticated libsasl2-dev libssl-dev locales locales-all
-    - pip install --use-deprecated=legacy-resolver -r requirements.txt --default-timeout=180 -i https://pypi.lcsb.uni.lu/simple/
-    - pip install --use-deprecated=legacy-resolver -r requirements-dev.txt --default-timeout=180 -i https://pypi.lcsb.uni.lu/simple/
+    - pip install -r requirements.txt --default-timeout=180 -i https://pypi.lcsb.uni.lu/simple/
+    - pip install -r requirements-dev.txt --default-timeout=180 -i https://pypi.lcsb.uni.lu/simple/
 
 test_postgres:
     <<: *test_definition
@@ -89,8 +89,8 @@ build_debian:
     - curl -sL https://deb.nodesource.com/setup_14.x | bash -
     - DEBIAN_FRONTEND=noninteractive apt-get install -y nodejs
 
-    - pip install --use-deprecated=legacy-resolver -r requirements.txt --default-timeout=180 -i https://pypi.lcsb.uni.lu/simple/
-    - pip install --use-deprecated=legacy-resolver -r requirements-dev.txt --default-timeout=180 -i https://pypi.lcsb.uni.lu/simple/
+    - pip install -r requirements.txt --default-timeout=180 -i https://pypi.lcsb.uni.lu/simple/
+    - pip install -r requirements-dev.txt --default-timeout=180 -i https://pypi.lcsb.uni.lu/simple/
 
     - export DEBFULLNAME="Piotr Gawron"
     - export DEBEMAIL="piotr.gawron@uni.lu"