go.mod: require go-delve/liner instead of peterh/liner (#2905)

Use of `replace` in go.mod breaks delve installation using
`go install`. (see https://github.com/golang/go/issues/40276)
Workaround this limitation by explicitly require the fork
github.com/go-delve/liner.

go-delve/liner@v1.2.2-1 already has go.mod module name fixed
to be github.com/go-delve/liner.

Fixes go-delve/delve#2904

vendor/github.com/go-delve/liner/input_linux.go

@@ -0,0 +1,29 @@
+//go:build linux
+// +build linux
+
+package liner
+
+import "syscall"
+
+const (
+	getTermios = syscall.TCGETS
+	setTermios = syscall.TCSETS
+)
+
+const (
+	icrnl  = syscall.ICRNL
+	inpck  = syscall.INPCK
+	istrip = syscall.ISTRIP
+	ixon   = syscall.IXON
+	opost  = syscall.OPOST
+	cs8    = syscall.CS8
+	isig   = syscall.ISIG
+	icanon = syscall.ICANON
+	iexten = syscall.IEXTEN
+)
+
+type termios struct {
+	syscall.Termios
+}
+
+const cursorColumn = false