[DOC/CI] Store doc as tar archive (#2448)

Summary:
At the time of release, we need to download doc built by CI.
CircleCI does not have feature to download multiple files.

This commit add the archive of built documentations as
CI artifact so that the whole documentation can be downloaded
at once.

Resolves https://github.com/pytorch/audio/issues/2340

Pull Request resolved: https://github.com/pytorch/audio/pull/2448

Reviewed By: hwangjeff

Differential Revision: D36942077

Pulled By: mthrok

fbshipit-source-id: 61dde0d71841434a3d0624404d99911aa6956f88

.circleci/config.yml

@@ -827,6 +827,9 @@ jobs:
             source /usr/local/etc/profile.d/conda.sh && conda activate python${PYTHON_VERSION}
             cd docs
             make 'SPHINXOPTS=-W' html
+            cd build
+            tar -czf artifact.tar.gz html
+            mv artifact.tar.gz html
           environment:
             BUILD_GALLERY: 1
           no_output_timeout: 30m

.circleci/config.yml.in

@@ -827,6 +827,9 @@ jobs:
             source /usr/local/etc/profile.d/conda.sh && conda activate python${PYTHON_VERSION}
             cd docs
             make 'SPHINXOPTS=-W' html
+            cd build
+            tar -czf artifact.tar.gz html
+            mv artifact.tar.gz html
           environment:
             BUILD_GALLERY: 1
           no_output_timeout: 30m