diff --git a/plotter/go.mod b/plotter/go.mod
index d459a8d..20c4743 100644
--- a/plotter/go.mod
+++ b/plotter/go.mod
@@ -16,6 +16,6 @@ require (
 	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 // indirect
 	github.com/phpdave11/gofpdf v1.4.2 // indirect
 	golang.org/x/image v0.0.0-20210216034530-4410531fe030 // indirect
-	golang.org/x/sys v0.0.0-20210304124612-50617c2ba197 // indirect
+	golang.org/x/sys v0.1.0 // indirect
 	golang.org/x/text v0.3.5 // indirect
 )
diff --git a/plotter/go.sum b/plotter/go.sum
index b86a343..25e861e 100644
--- a/plotter/go.sum
+++ b/plotter/go.sum
@@ -62,8 +62,9 @@ golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5h
 golang.org/x/sys v0.0.0-20190312061237-fead79001313/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210304124612-50617c2ba197 h1:7+SpRyhoo46QjKkYInQXpcfxx3TYFEYkn131lwGE9/0=
 golang.org/x/sys v0.0.0-20210304124612-50617c2ba197/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.1.0 h1:kunALQeHf1/185U1i0GOB/fy1IPRDDpuoOOqRReG57U=
+golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.5 h1:i6eZZ+zk0SOf0xgBpEpPD18qWcJda6q1sxt3S0kzyUQ=
 golang.org/x/text v0.3.5/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=