Remove unneeded docker pull of pandoc image

Signed-off-by: Josh Dolitsky <[email protected]>

Author: jdolitsky

.github/workflows/docs-and-linting.yml

@@ -28,7 +28,6 @@ jobs:
           GOPATH: /home/runner/work/image-spec/image-spec/go
         run: |
           export PATH=$GOPATH/bin:$PATH
-          docker pull quay.io/oci/pandoc:1.17.0.3-2.fc25.x86_64
           cd go/src/github.com/opencontainers/image-spec
           make install.tools
           go get -u github.com/alecthomas/gometalinter