Add module files for go-ipfs-as-a-library example

docs/examples/go-ipfs-as-a-library/go.mod

+module github.com/ipfs/go-ipfs/examples/go-ipfs-as-a-library
+
+go 1.14
+
+require (
+	github.com/ipfs/go-ipfs v0.5.0-rc1.0.20200411010526-5ecf44a88217
+	github.com/ipfs/go-ipfs-config v0.4.0
+	github.com/ipfs/go-ipfs-files v0.0.8
+	github.com/ipfs/interface-go-ipfs-core v0.2.6
+	github.com/libp2p/go-libp2p-core v0.5.1
+	github.com/libp2p/go-libp2p-peerstore v0.2.3
+	github.com/multiformats/go-multiaddr v0.2.1
+)