chore: use gofumpt (#82)

## Overview

Unify formatting with `celestia-node` and other Celestia projects in the
future.

.golangci.yml

@@ -63,6 +63,6 @@ linters-settings:
   misspell:
     locale: US
   goimports:
-    local-prefixes: github.com/celestiaorg/celestia-node
+    local-prefixes: github.com/celestiaorg
   dupl:
     threshold: 200

Makefile

@@ -34,6 +34,7 @@ fmt:
 	@find . -name '*.go' -type f -not -path "*.git*" -not -name '*.pb.go' -not -name '*pb_test.go' | xargs gofmt -w -s
 	@find . -name '*.go' -type f -not -path "*.git*"  -not -name '*.pb.go' -not -name '*pb_test.go' | xargs goimports -w -local github.com/celestiaorg
 	@go mod tidy -compat=1.17
+	@gofumpt -w -extra .
 	@cfmt -w -m=100 ./...
 .PHONY: fmt
 

fraudserv/store.go

@@ -15,9 +15,7 @@ import (
 	"github.com/celestiaorg/go-fraud"
 )
 
-var (
-	storePrefix = "fraud"
-)
+var storePrefix = "fraud"
 
 // put adds a Fraud Proof to the datastore with the given hash as the key.
 func put(ctx context.Context, ds datastore.Datastore, hash string, value []byte) error {