Update Fabric chaincode Dockerfile

[lanasta]

Building with this Dockerfile currently breaks because the batchpin folder isn't being copied

#10 5.161 chaincode/contract.go:8:2: no required module provides package github.com/hyperledger/firefly/chaincode-go/batchpin; to add it:
#10 5.161       go get github.com/hyperledger/firefly/chaincode-go/batchpin
------
executor failed running [/bin/sh -c ls -la ./     && GO111MODULE=on GOOS=linux CGO_ENABLED=0 go build -o firefly.bin firefly.go]: exit code: 1```

[codecov-commenter]

Codecov Report

Merging #1302 (53f7a4b) into main (4df24f3) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              main     #1302   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          308       308           
  Lines        20717     20717           
=========================================
  Hits         20717     20717