chore(dep): update yamux

This version of yamux prevents a class of bugs where a connection could be
erroneously declared dead due to keepalive messages getting stuck behind other writes.

go.mod

@@ -5,5 +5,5 @@ go 1.13
 require (
 	github.com/libp2p/go-libp2p-core v0.7.0
 	github.com/libp2p/go-libp2p-testing v0.3.0
-	github.com/libp2p/go-yamux v1.4.0
+	github.com/libp2p/go-yamux v1.4.1
 )

go.sum

@@ -53,8 +53,8 @@ github.com/libp2p/go-libp2p-testing v0.3.0/go.mod h1:efZkql4UZ7OVsEfaxNHZPzIehts
 github.com/libp2p/go-maddr-filter v0.1.0/go.mod h1:VzZhTXkMucEGGEOSKddrwGiOv0tUhgnKqNEmIAz/bPU=
 github.com/libp2p/go-msgio v0.0.6/go.mod h1:4ecVB6d9f4BDSL5fqvPiC4A3KivjWn+Venn/1ALLMWA=
 github.com/libp2p/go-openssl v0.0.7/go.mod h1:unDrJpgy3oFr+rqXsarWifmJuNnJR4chtO1HmaZjggc=
-github.com/libp2p/go-yamux v1.4.0 h1:7nqe0T95T2CWh40IdJ/tp8RMor4ubc9/wYZpB2a/Hx0=
-github.com/libp2p/go-yamux v1.4.0/go.mod h1:fr7aVgmdNGJK+N1g+b6DW6VxzbRCjCOejR/hkmpooHE=
+github.com/libp2p/go-yamux v1.4.1 h1:P1Fe9vF4th5JOxxgQvfbOHkrGqIZniTLf+ddhZp8YTI=
+github.com/libp2p/go-yamux v1.4.1/go.mod h1:fr7aVgmdNGJK+N1g+b6DW6VxzbRCjCOejR/hkmpooHE=
 github.com/minio/blake2b-simd v0.0.0-20160723061019-3f5f724cb5b1 h1:lYpkrQH5ajf0OXOcUbGjvZxxijuBwbbmlSxLiuofa+g=
 github.com/minio/blake2b-simd v0.0.0-20160723061019-3f5f724cb5b1/go.mod h1:pD8RvIylQ358TN4wwqatJ8rNavkEINozVn9DtGI3dfQ=
 github.com/minio/sha256-simd v0.1.1-0.20190913151208-6de447530771/go.mod h1:B5e1o+1/KgNmWrSQK08Y6Z1Vb5pwIktudl0J58iy0KM=