Upgrade tcell to v2.2.1.

go.mod

@@ -3,7 +3,7 @@ module github.com/rivo/tview
 go 1.12
 
 require (
-	github.com/gdamore/tcell/v2 v2.2.0
+	github.com/gdamore/tcell/v2 v2.2.1
 	github.com/lucasb-eyer/go-colorful v1.2.0
 	github.com/mattn/go-runewidth v0.0.10
 	github.com/rivo/uniseg v0.2.0

go.sum

@@ -2,6 +2,8 @@ github.com/gdamore/encoding v1.0.0 h1:+7OoQ1Bc6eTm5niUzBa0Ctsh6JbMW6Ra+YNuAtDBdk
 github.com/gdamore/encoding v1.0.0/go.mod h1:alR0ol34c49FCSBLjhosxzcPHQbf2trDkoo5dl+VrEg=
 github.com/gdamore/tcell/v2 v2.2.0 h1:vSyEgKwraXPSOkvCk7IwOSyX+Pv3V2cV9CikJMXg4U4=
 github.com/gdamore/tcell/v2 v2.2.0/go.mod h1:cTTuF84Dlj/RqmaCIV5p4w8uG1zWdk0SF6oBpwHp4fU=
+github.com/gdamore/tcell/v2 v2.2.1 h1:Gt8wk0jd5pIK2CyXNo/fqwxNWf726j1lQjEDdfbnqTc=
+github.com/gdamore/tcell/v2 v2.2.1/go.mod h1:cTTuF84Dlj/RqmaCIV5p4w8uG1zWdk0SF6oBpwHp4fU=
 github.com/lucasb-eyer/go-colorful v1.0.3/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
 github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
 github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=