all: remove github.com/pkg/errors dependency

block_conv.go

@@ -2,9 +2,8 @@ package slack
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
-
-	"github.com/pkg/errors"
 )
 
 type sumtype struct {

go.mod

@@ -1,12 +1,11 @@
 module github.com/slack-go/slack
 
+go 1.16
+
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/go-test/deep v1.0.4
 	github.com/gorilla/websocket v1.4.2
-	github.com/pkg/errors v0.8.0
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/stretchr/testify v1.2.2
 )
-
-go 1.16

go.sum

@@ -4,8 +4,6 @@ github.com/go-test/deep v1.0.4 h1:u2CU3YKy9I2pmu9pX0eq50wCgjfGIt539SqR7FbHiho=
 github.com/go-test/deep v1.0.4/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
 github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0Ufc=
 github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
-github.com/pkg/errors v0.8.0 h1:WdK/asTD0HN+q6hsWO3/vpuAkAr+tw6aNJNDFFf0+qw=
-github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=

socketmode/socketmode_test.go

@@ -3,12 +3,11 @@ package socketmode
 import (
 	"bytes"
 	"encoding/json"
+	"errors"
 	"reflect"
 	"testing"
 
 	"github.com/slack-go/slack/slackevents"
-
-	"github.com/pkg/errors"
 )
 
 const (