cli: upgrade to go1.18.5

[bassosimone]

Because we cannot upgrade directly to go1.19 (issue #2211) because of issue #2222, let's update to go1.18.5. This entails ensuring that the oohttp and oocrypto versions we're using are 100% compatible with go1.18.5 (they're currently using go1.19, unfortunately). Here's what changed between go1.18.3 and go1.18.5 in src/net/http:

% git diff go1.18.3...go1.18.5 -- ./src/net/http
diff --git a/src/net/http/header.go b/src/net/http/header.go
index 6487e5025d..6437f2d2c0 100644
--- a/src/net/http/header.go
+++ b/src/net/http/header.go
@@ -103,6 +103,12 @@ func (h Header) Clone() Header {
 	sv := make([]string, nv) // shared backing array for headers' values
 	h2 := make(Header, len(h))
 	for k, vv := range h {
+		if vv == nil {
+			// Preserve nil values. ReverseProxy distinguishes
+			// between nil and zero-length header values.
+			h2[k] = nil
+			continue
+		}
 		n := copy(sv, vv)
 		h2[k] = sv[:n:n]
 		sv = sv[n:]
diff --git a/src/net/http/header_test.go b/src/net/http/header_test.go
index 57d16f51a5..0b13d311ac 100644
--- a/src/net/http/header_test.go
+++ b/src/net/http/header_test.go
@@ -248,6 +248,11 @@ func TestCloneOrMakeHeader(t *testing.T) {
 			in:   Header{"foo": {"bar"}},
 			want: Header{"foo": {"bar"}},
 		},
+		{
+			name: "nil value",
+			in:   Header{"foo": nil},
+			want: Header{"foo": nil},
+		},
 	}
 
 	for _, tt := range tests {
diff --git a/src/net/http/serve_test.go b/src/net/http/serve_test.go
index fb18cb2c6f..3f3e1421a9 100644
--- a/src/net/http/serve_test.go
+++ b/src/net/http/serve_test.go
@@ -6250,6 +6250,7 @@ func TestUnsupportedTransferEncodingsReturn501(t *testing.T) {
 		"fugazi",
 		"foo-bar",
 		"unknown",
+		"\rchunked",
 	}
 
 	for _, badTE := range unsupportedTEs {
diff --git a/src/net/http/transfer.go b/src/net/http/transfer.go
index 6d51178ee9..de69d835ac 100644
--- a/src/net/http/transfer.go
+++ b/src/net/http/transfer.go
@@ -640,7 +640,7 @@ func (t *transferReader) parseTransferEncoding() error {
 	if len(raw) != 1 {
 		return &unsupportedTEError{fmt.Sprintf("too many transfer encodings: %q", raw)}
 	}
-	if !ascii.EqualFold(textproto.TrimString(raw[0]), "chunked") {
+	if !ascii.EqualFold(raw[0], "chunked") {
 		return &unsupportedTEError{fmt.Sprintf("unsupported transfer encoding: %q", raw[0])}
 	}
 

And here's what changed in src/crypto:

% git diff go1.18.3...go1.18.5 -- ./src/crypto

That is, nothing actually changes.

From this, it stems that we should only update oohttp (which we did in ooni/oohttp#31) and we should not change anything in oocrypto. Yet, we may need some extra changes to support go1.19 as well.