cue: use v2 of abitrary precision decimal package

This fixes a major bug that currently does not
affect cue but is dangerous to let linger.

Change-Id: Ibd3e7581fa1fc399aa0ad45cb3f0bb30e334b034
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/2363
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/cue/binop.go b/cue/binop.go
index b7daf6b..791bfe4 100644
--- a/cue/binop.go
+++ b/cue/binop.go
@@ -23,7 +23,7 @@
 	"time"
 
 	"cuelang.org/go/cue/token"
-	"github.com/cockroachdb/apd"
+	"github.com/cockroachdb/apd/v2"
 )
 
 // binSrc returns a baseValue representing a binary expression of the given
diff --git a/cue/context.go b/cue/context.go
index ff81001..9fc5d13 100644
--- a/cue/context.go
+++ b/cue/context.go
@@ -15,7 +15,7 @@
 package cue
 
 import (
-	"github.com/cockroachdb/apd"
+	"github.com/cockroachdb/apd/v2"
 )
 
 // context manages evaluation state.
diff --git a/cue/export.go b/cue/export.go
index dbb4d41..54f5923 100644
--- a/cue/export.go
+++ b/cue/export.go
@@ -25,7 +25,7 @@
 
 	"cuelang.org/go/cue/ast"
 	"cuelang.org/go/cue/token"
-	"github.com/cockroachdb/apd"
+	"github.com/cockroachdb/apd/v2"
 )
 
 func doEval(m options) bool {
diff --git a/cue/go.go b/cue/go.go
index 70c05d0..cdf21db 100644
--- a/cue/go.go
+++ b/cue/go.go
@@ -28,7 +28,7 @@
 	"cuelang.org/go/cue/parser"
 	"cuelang.org/go/cue/token"
 	"cuelang.org/go/internal"
-	"github.com/cockroachdb/apd"
+	"github.com/cockroachdb/apd/v2"
 )
 
 // This file contains functionality for converting Go to CUE.
diff --git a/cue/lit.go b/cue/lit.go
index 2429b62..5fecf92 100644
--- a/cue/lit.go
+++ b/cue/lit.go
@@ -19,7 +19,7 @@
 
 	"cuelang.org/go/cue/ast"
 	"cuelang.org/go/cue/literal"
-	"github.com/cockroachdb/apd"
+	"github.com/cockroachdb/apd/v2"
 )
 
 type numInfo struct {
diff --git a/cue/lit_test.go b/cue/lit_test.go
index fe8a9e5..cee9efe 100644
--- a/cue/lit_test.go
+++ b/cue/lit_test.go
@@ -20,7 +20,7 @@
 	"testing"
 
 	"cuelang.org/go/cue/ast"
-	"github.com/cockroachdb/apd"
+	"github.com/cockroachdb/apd/v2"
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
 )
diff --git a/cue/types.go b/cue/types.go
index 2ca3ede..c63021b 100644
--- a/cue/types.go
+++ b/cue/types.go
@@ -28,7 +28,7 @@
 	"cuelang.org/go/cue/ast"
 	"cuelang.org/go/cue/errors"
 	"cuelang.org/go/cue/token"
-	"github.com/cockroachdb/apd"
+	"github.com/cockroachdb/apd/v2"
 )
 
 // Kind determines the underlying type of a Value.
diff --git a/cue/value.go b/cue/value.go
index cc596d7..88a8af2 100644
--- a/cue/value.go
+++ b/cue/value.go
@@ -23,7 +23,7 @@
 
 	"cuelang.org/go/cue/ast"
 	"cuelang.org/go/cue/token"
-	"github.com/cockroachdb/apd"
+	"github.com/cockroachdb/apd/v2"
 )
 
 type value interface {
diff --git a/go.mod b/go.mod
index 73bde76..338429e 100644
--- a/go.mod
+++ b/go.mod
@@ -1,7 +1,8 @@
 module cuelang.org/go
 
 require (
-	github.com/cockroachdb/apd v1.1.0
+	github.com/cockroachdb/apd v1.1.0 // indirect
+	github.com/cockroachdb/apd/v2 v2.0.1
 	github.com/emicklei/proto v1.6.11
 	github.com/ghodss/yaml v1.0.0
 	github.com/google/go-cmp v0.2.0
@@ -9,7 +10,6 @@
 	github.com/kylelemons/godebug v1.1.0
 	github.com/lib/pq v1.0.0 // indirect
 	github.com/mpvl/unique v0.0.0-20150818121801-cbe035fff7de
-	github.com/pkg/errors v0.8.0 // indirect
 	github.com/retr0h/go-gilt v0.0.0-20190206215556-f73826b37af2
 	github.com/spf13/cobra v0.0.3
 	github.com/spf13/pflag v1.0.3
diff --git a/go.sum b/go.sum
index 1bc59e3..d53173b 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,7 @@
 github.com/cockroachdb/apd v1.1.0 h1:3LFP3629v+1aKXU5Q37mxmRxX/pIu1nijXydLShEq5I=
 github.com/cockroachdb/apd v1.1.0/go.mod h1:8Sl8LxpKi29FqWXR16WEFZRNSz3SoPzUzeMeY4+DwBQ=
+github.com/cockroachdb/apd/v2 v2.0.1 h1:y1Rh3tEU89D+7Tgbw+lp52T6p/GJLpDmNvr10UWqLTE=
+github.com/cockroachdb/apd/v2 v2.0.1/go.mod h1:DDxRlzC2lo3/vSlmSoS7JkqbbrARPuFOGr0B9pvN3Gw=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/emicklei/proto v1.6.11 h1:KZHE0+iwVLth2D/K8jat9rs70K6TFWyol8ihrOdrbM0=
 github.com/emicklei/proto v1.6.11/go.mod h1:rn1FgRS/FANiZdD2djyH7TMA9jdRDcYQ9IEN9yvjX0A=