go mod tidy ipfs library example

The code example for using IPFS as a library doesn't run unless indirect dependencies are updated:

```
$ go version
go version go1.17 linux/amd64
$ uname -a
Linux home 4.19.0-17-amd64 #1 SMP Debian 4.19.194-3 (2021-07-18) x86_64 GNU/Linux
$ go run main.go
go: github.com/ipfs/go-ipfs@v0.9.1 requires
	github.com/ipfs/go-bitswap@v0.4.0: missing go.sum entry; to add it:
	go mod download github.com/ipfs/go-bitswap
go: github.com/ipfs/go-ipfs@v0.9.1 requires
	github.com/ipfs/go-bitswap@v0.4.0: missing go.sum entry; to add it:
	go mod download github.com/ipfs/go-bitswap
```

Remedied by:

```
$ go mod tidy
$ go run main.go
-- Getting an IPFS node running --
Spawning node on a temporary repo
    ...
```

Also, require go version 1.16, otherwise, example can fail under go
1.15 with errors like:

```
go build github.com/lucas-clemente/quic-go/internal/qtls:
    build constraints exclude all Go files in
    /home/jbouwman/go/pkg/mod/github.com/lucas-clemente/quic-go@v0.23.0/internal/qtls
```

(cherry picked from commit cb189c7)

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

@@ -1,14 +1,14 @@
 module github.com/ipfs/go-ipfs/examples/go-ipfs-as-a-library
 
-go 1.15
+go 1.16
 
 require (
 	github.com/ipfs/go-ipfs v0.9.1
-	github.com/ipfs/go-ipfs-config v0.14.0
+	github.com/ipfs/go-ipfs-config v0.16.0
 	github.com/ipfs/go-ipfs-files v0.0.8
-	github.com/ipfs/interface-go-ipfs-core v0.4.0
-	github.com/libp2p/go-libp2p-core v0.8.6
-	github.com/multiformats/go-multiaddr v0.3.3
+	github.com/ipfs/interface-go-ipfs-core v0.5.1
+	github.com/libp2p/go-libp2p-core v0.9.0
+	github.com/multiformats/go-multiaddr v0.4.0
 )
 
 replace github.com/ipfs/go-ipfs => ./../../..