Update dependencies. (#657)

diff --git a/go.mod b/go.mod
index ca476f6..69bbb83 100644
--- a/go.mod
+++ b/go.mod
@@ -6,6 +6,6 @@
 	github.com/chzyer/logex v1.1.10 // indirect
 	github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e
 	github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1 // indirect
-	github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639
-	golang.org/x/sys v0.0.0-20191204072324-ce4227a45e2e // indirect
+	github.com/ianlancetaylor/demangle v0.0.0-20210905161508-09a460cdf81d
+	golang.org/x/sys v0.0.0-20211007075335-d3039528d8ac // indirect
 )
diff --git a/go.sum b/go.sum
index a5e6c33..5140fc1 100644
--- a/go.sum
+++ b/go.sum
@@ -4,9 +4,7 @@
 github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
 github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1 h1:q763qf9huN11kDQavWsoZXJNW3xEE4JJyHa5Q25/sd8=
 github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMnBNeIyt5eFwwo7qiLfzFZmjNmxjkiQlU=
-github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6 h1:UDMh68UUwekSh5iP2OMhRRZJiiBccgV7axzUG8vi56c=
-github.com/ianlancetaylor/demangle v0.0.0-20181102032728-5e5cf60278f6/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
-github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639 h1:mV02weKRL81bEnm8A0HT1/CAelMQDBuQIfLw8n+d6xI=
-github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
-golang.org/x/sys v0.0.0-20191204072324-ce4227a45e2e h1:9vRrk9YW2BTzLP0VCB9ZDjU4cPqkg+IDWL7XgxA1yxQ=
-golang.org/x/sys v0.0.0-20191204072324-ce4227a45e2e/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+github.com/ianlancetaylor/demangle v0.0.0-20210905161508-09a460cdf81d h1:uGg2frlt3IcT7kbV6LEp5ONv4vmoO2FW4qSO+my/aoM=
+github.com/ianlancetaylor/demangle v0.0.0-20210905161508-09a460cdf81d/go.mod h1:aYm2/VgdVmcIU8iMfdMvDMsRAQjcfZSKFby6HOFvi/w=
+golang.org/x/sys v0.0.0-20211007075335-d3039528d8ac h1:oN6lz7iLW/YC7un8pq+9bOLyXrprv2+DKfkJY+2LJJw=
+golang.org/x/sys v0.0.0-20211007075335-d3039528d8ac/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=