Update buildkit

- updated buildkit to current code in master via:

  go mod edit -require github.com/moby/buildkit@master && go mod tidy && ./hack/update-vendor

Signed-off-by: Alex Couture-Beil <alex@earthly.dev>

vendor/github.com/moby/buildkit/util/gitutil/git_protocol.go

@@ -0,0 +1,46 @@
+package gitutil
+
+import (
+	"strings"
+
+	"github.com/moby/buildkit/util/sshutil"
+)
+
+const (
+	HTTPProtocol = iota + 1
+	HTTPSProtocol
+	SSHProtocol
+	GitProtocol
+	UnknownProtocol
+)
+
+// ParseProtocol parses a git URL and returns the remote url and protocol type
+func ParseProtocol(remote string) (string, int) {
+	prefixes := map[string]int{
+		"http://":  HTTPProtocol,
+		"https://": HTTPSProtocol,
+		"git://":   GitProtocol,
+		"ssh://":   SSHProtocol,
+	}
+	protocolType := UnknownProtocol
+	for prefix, potentialType := range prefixes {
+		if strings.HasPrefix(remote, prefix) {
+			remote = strings.TrimPrefix(remote, prefix)
+			protocolType = potentialType
+		}
+	}
+
+	if protocolType == UnknownProtocol && sshutil.IsImplicitSSHTransport(remote) {
+		protocolType = SSHProtocol
+	}
+
+	// remove name from ssh
+	if protocolType == SSHProtocol {
+		parts := strings.SplitN(remote, "@", 2)
+		if len(parts) == 2 {
+			remote = parts[1]
+		}
+	}
+
+	return remote, protocolType
+}