Add docker image build into github workflow

[Gnnng]

The current master has failure in docker build. It should be fixed and also add a image build workflow for pull-request

   Compiling libp2p-plaintext v0.15.0
   Compiling libp2p-floodsub v0.15.0
   Compiling libp2p-identify v0.15.0
   Compiling libp2p-secio v0.15.0
error: failed to run custom build command for `advanca-runtime v0.2.0 (/advanca/runtime)`

Caused by:
  process didn't exit successfully: `/advanca/target/release/build/advanca-runtime-9fdd27bb944d06d6/build-script-build` (exit code: 1)
--- stdout
Executing build command: "rustup" "run" "nightly" "cargo" "rustc" "--target=wasm32-unknown-unknown" "--manifest-path=/advanca/target/release/wbuild/advanca-runtime/Cargo.toml" "--color=always" "--release"

--- stderr
    Updating crates.io index
 Downloading crates ...
...
   Compiling serde_derive v1.0.111
   Compiling cargo_metadata v0.10.0
   Compiling substrate-wasm-builder v1.0.11
   Compiling wasm-build-runner-impl v1.0.0 (/advanca/target/release/wbuild-runner/advanca-runtime15053993525039888284)
    Finished release [optimized] target(s) in 1m 26s
     Running `/advanca/target/release/wbuild-runner/advanca-runtime15053993525039888284/target/release/wasm-build-runner-impl`
error: failed to download `futures v0.3.4`

Caused by:
  unable to get packages from source

Caused by:
  failed to parse manifest at `/usr/local/cargo/registry/src/github.com-1ecc6299db9ec823/futures-0.3.4/Cargo.toml`

Caused by:
  readme file with name '../README.md' was not found

warning: build failed, waiting for other jobs to finish...
error: build failed
ERROR: Service 'node' failed to build: The command '/bin/sh -c rustup toolchain install nightly &&     rustup target add wasm32-unknown-unknown --toolchain nightly &&     cargo build --$PROFILE' returned a non-zero code: 101