Zed update through "remove mapstructure" by mccanne

This is an auto-generated commit with a Zed dependency update. The Zed PR
brimdata/super#2703, authored by @mccanne,
has been merged.

remove mapstructure

I have tripped over mapstructure one too many times so this commit
removes it.  When/if the extra round-trip through JSON adds
measurable overhead to Zed query times, we can revisit this and
hopefully mapstructure will be more mature.  For now, I wanted to
add order.Which to proc.Sort and similar but mapstructure cannot
handle custom JSON unmarshalers so this caused unpack to fail
for apparently no reason.

See mitchellh/mapstructure#115

go.mod

@@ -3,7 +3,7 @@ module github.com/brimdata/brimcap
 go 1.16
 
 require (
-	github.com/brimdata/zed v0.29.1-0.20210511005542-ff45c9d1cac7
+	github.com/brimdata/zed v0.29.1-0.20210511010802-730d19c91f99
 	github.com/fsnotify/fsnotify v1.4.9
 	github.com/golang/mock v1.5.0
 	github.com/google/gopacket v1.1.19

go.sum

@@ -18,8 +18,8 @@ github.com/axiomhq/hyperloglog v0.0.0-20191112132149-a4c4c47bc57f/go.mod h1:2stg
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
-github.com/brimdata/zed v0.29.1-0.20210511005542-ff45c9d1cac7 h1:/5dedeHdp6Vmjbgmu/ek2rJJ3IfkcKqDDpzRKyxTY7M=
-github.com/brimdata/zed v0.29.1-0.20210511005542-ff45c9d1cac7/go.mod h1:rLH9+urG49Qt7Kt2y4RQA/Bge7VRJgn1M5ftHV6N0QY=
+github.com/brimdata/zed v0.29.1-0.20210511010802-730d19c91f99 h1:DRndsiJ+jEgQqGwT7Ti7E7tHluVqf49jP9owT0Ck64Y=
+github.com/brimdata/zed v0.29.1-0.20210511010802-730d19c91f99/go.mod h1:qfj6p4h0TQIyKtyuqltO3jneIUP6C1hRS5THEul7Rls=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
 github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/coreos/etcd v3.3.10+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE=
@@ -105,8 +105,6 @@ github.com/mattn/go-runewidth v0.0.10/go.mod h1:RAqKPSqVFrSLVXbA8x7dzmKdmGzieGRC
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/mapstructure v1.1.2/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
-github.com/mitchellh/mapstructure v1.3.3 h1:SzB1nHZ2Xi+17FP0zVQBHIZqvwRN9408fJO8h+eeNA8=
-github.com/mitchellh/mapstructure v1.3.3/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/reflect2 v0.0.0-20180701023420-4b7aa43c6742/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=