chore: upgrade psiphon and go-cmp (#669)

I have experimented with a new approach for embedding psiphon in
7fc0bcd97c.

It seems the build is still building and the experiment is still
running. With the new approach, we're now vendoring less dependencies,
which hopefully puts us in the right track to, one day, import
Psiphon as a normal Go dependency.

I'll make sure to report to the Psiphon team what is currently
preventing us from importing their ClientLibrary directly.

This work is part of https://github.com/ooni/probe/issues/1894.

As part of running the update, I run `go get -u -v ./...`, which
led to go-cmp also being updated in the process.

go.mod

@@ -11,12 +11,10 @@ require (
 	github.com/alecthomas/units v0.0.0-20211218093645-b94a6e3cc137 // indirect
 	github.com/apex/log v1.9.0
 	github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5
-	github.com/creack/goselect v0.1.2 // indirect
 	github.com/cretz/bine v0.2.0
-	github.com/dchest/siphash v1.2.2 // indirect
 	github.com/fatih/color v1.13.0
 	github.com/fsnotify/fsnotify v1.5.1 // indirect
-	github.com/google/go-cmp v0.5.5
+	github.com/google/go-cmp v0.5.6
 	github.com/google/martian/v3 v3.2.1
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510
 	github.com/google/uuid v1.3.0
@@ -36,7 +34,7 @@ require (
 	github.com/ooni/go-libtor v1.1.4
 	github.com/ooni/oohttp v0.0.0-20220118112935-940b7f7db71e
 	github.com/ooni/probe-assets v0.7.0
-	github.com/ooni/psiphon v0.9.0
+	github.com/ooni/psiphon/tunnel-core v0.0.0-20220121102537-7fc0bcd97c5f
 	github.com/oschwald/geoip2-golang v1.5.0
 	github.com/pborman/getopt/v2 v2.1.0
 	github.com/pion/interceptor v0.1.5 // indirect