Install both lightning and pytorch-lightning in docker image (#18898)

(cherry picked from commit 4af77c6)

Author: awaelchli

dockers/release/Dockerfile

@@ -24,8 +24,6 @@ ARG LIGHTNING_VERSION=""
 
 COPY ./ /home/lightning/
 
-ENV PACKAGE_NAME=pytorch
-
 # install dependencies
 RUN \
     cd /home && \
@@ -42,7 +40,8 @@ RUN \
     # otherwise there is collision with folder name and pkg name on Pypi
     cd lightning && \
     pip install setuptools==59.5.0 && \
-    pip install '.[extra,loggers,strategies]' --no-cache-dir && \
+    PACKAGE_NAME=lightning pip install '.[extra,loggers,strategies]' --no-cache-dir && \
+    PACKAGE_NAME=pytorch pip install '.[extra,loggers,strategies]' --no-cache-dir && \
     cd .. && \
     rm -rf lightning