remove frozenrequirements.txt from Dockerfile

build/Dockerfile

@@ -14,9 +14,8 @@
 
 FROM python:3.7-slim-buster
 
-COPY requirements.txt frozenrequirements.txt ./
+COPY requirements.txt ./
 
-RUN pip install -r frozenrequirements.txt
 RUN pip install -r requirements.txt
 
 COPY ./app /app