Use LABEL maintainer instead of Maintainer attr

Author: kaushikb11

dockers/base-ipu/Dockerfile

@@ -14,7 +14,7 @@
 
 FROM ubuntu:20.04
 
-MAINTAINER PyTorchLightning <https://github.com/PyTorchLightning>
+LABEL maintainer="PyTorchLightning <https://github.com/PyTorchLightning>"
 
 ARG PYTHON_VERSION=3.8
 ARG PYTORCH_VERSION=1.7

dockers/base-xla/Dockerfile

@@ -14,7 +14,7 @@
 
 FROM google/cloud-sdk:slim
 
-MAINTAINER PyTorchLightning <https://github.com/PyTorchLightning>
+LABEL maintainer="PyTorchLightning <https://github.com/PyTorchLightning>"
 
 # CALL: docker image build -t pytorch-lightning:XLA-extras-py3.6 -f dockers/base-xla/Dockerfile . --build-arg PYTHON_VERSION=3.6
 # This Dockerfile installs pytorch/xla 3.7 wheels. There are also 3.6 wheels available; see below.

dockers/ipu-ci-runner/Dockerfile

@@ -17,7 +17,7 @@ ARG PYTORCH_VERSION=1.7
 
 FROM pytorchlightning/pytorch_lightning:base-ipu-py${PYTHON_VERSION}-torch${PYTORCH_VERSION}
 
-MAINTAINER PyTorchLightning <https://github.com/PyTorchLightning>
+LABEL maintainer="PyTorchLightning <https://github.com/PyTorchLightning>"
 
 RUN echo "ALL ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers
 

dockers/nvidia/Dockerfile

@@ -15,7 +15,7 @@
 # https://docs.nvidia.com/deeplearning/frameworks/pytorch-release-notes
 FROM nvcr.io/nvidia/pytorch:21.04-py3
 
-MAINTAINER PyTorchLightning <https://github.com/PyTorchLightning>
+LABEL maintainer="PyTorchLightning <https://github.com/PyTorchLightning>"
 
 ARG LIGHTNING_VERSION=""
 

dockers/release/Dockerfile

@@ -17,7 +17,7 @@ ARG PYTORCH_VERSION=1.5
 
 FROM pytorchlightning/pytorch_lightning:base-cuda-py${PYTHON_VERSION}-torch${PYTORCH_VERSION}
 
-MAINTAINER PyTorchLightning <https://github.com/PyTorchLightning>
+LABEL maintainer="PyTorchLightning <https://github.com/PyTorchLightning>"
 
 ARG LIGHTNING_VERSION=""
 

dockers/tpu-tests/Dockerfile

@@ -17,7 +17,7 @@ ARG PYTORCH_VERSION=1.6
 
 FROM pytorchlightning/pytorch_lightning:base-xla-py${PYTHON_VERSION}-torch${PYTORCH_VERSION}
 
-MAINTAINER PyTorchLightning <https://github.com/PyTorchLightning>
+LABEL maintainer="PyTorchLightning <https://github.com/PyTorchLightning>"
 
 #SHELL ["/bin/bash", "-c"]