[FAB-12647] Add ignore for fabric-shim links
[FAB-12647] Add ignore for fabric-shim links

Adds an the linkcheck_ignore option for
fabric-shim.github.io URLs.

Change-Id: Ib22a1feee45ecc1f4d73e866a68eccc1f80740f7
Signed-off-by: Jason Clark <5f7a234d7e06050227a36ab26eb6bcddc509ddce@linux.vnet.ibm.com>

xixuejia/fabric,manish-sethi/fabric,stemlending/fabric,jimthematrix/fabric,manish-sethi/fabric-sidedb,stemlending/fabric,hyperledger/fabric,xixuejia/fabric,manish-sethi/fabric,stemlending/fabric,manish-sethi/fabric-sidedb,jimthematrix/fabric,manish-sethi/fabric-sidedb,binhn/fabric,muralisrini/fabric,manish-sethi/fabric-sidedb,stemlending/fabric,muralisrini/fabric,manish-sethi/fabric-sidedb,muralisrini/fabric,manish-sethi/fabric-sidedb,binhn/fabric,manish-sethi/fabric-sidedb,hyperledger/fabric,xixuejia/fabric,binhn/fabric