make version regex posix compliant so that it works on mac

[arner]

The kubernetes network does not start correctly on Mac due to a different interpretation of the regex by sed.

./test-network-k8s/network 
Fabric image versions: Peer (), CA ()
It seems some of the specified Fabric images are not available.

Examples for testing the fix:

# current: returns empty line on mac
docker run --rm hyperledger/fabric-peer:2.5 peer version | sed -ne 's/^ Version: v\?\(.*\)$/\1/p'

# now: works when executed in the linux OS of the container
docker run --rm hyperledger/fabric-peer:2.5 bash -c "peer version | sed -ne 's/^ Version: v\{0,1\}\(.*\)$/\1/p'"
2.5.9

# works on mac
docker run --rm hyperledger/fabric-peer:2.5 peer version | sed -ne 's/^ Version: v\{0,1\}\(.*\)$/\1/p'
2.5.9

# works without a 'v'
docker run --rm hyperledger/fabric-peer:2.5 bash -c "echo ' Version: 2.5.9' | sed -ne 's/^ Version: v\{0,1\}\(.*\)$/\1/p'"
2.5.9

[denyeart]

Thanks Arne!