fix(mod): use golang v1.20.4

there is some bug in golang internal libs that causes linter to fail on any golang less then 1.18 with following error:
* can't run linter goanalysis_metalinter: buildir: failed to load package gocql: could not load export data: no export data for "github.com/gocql/gocql"

.github/workflows/go.yml

@@ -17,7 +17,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v2
         with:
-          go-version: 1.14
+          go-version: 1.20.4
 
       - name: Linting
         run: |

Makefile

@@ -3,7 +3,6 @@ MAKEFILE_PATH := $(abspath $(dir $(abspath $(lastword $(MAKEFILE_LIST)))))
 
 GO111MODULE := on
 # GO_UPGRADE - do not remove this comment, used by scripts/go-upgrade.sh
-GOVERSION ?= 1.12
 GOOS := $(shell uname | tr '[:upper:]' '[:lower:]')
 GOARCH := $(shell go env GOARCH)
 

cmd/gemini/root.go

@@ -17,7 +17,6 @@ package main
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"math"
 	"net/http"
 	_ "net/http/pprof"
@@ -138,7 +137,7 @@ type testJob func(
 ) error
 
 func readSchema(confFile string) (*gemini.Schema, error) {
-	byteValue, err := ioutil.ReadFile(confFile)
+	byteValue, err := os.ReadFile(confFile)
 	if err != nil {
 		return nil, err
 	}

go.mod

@@ -1,6 +1,6 @@
 module github.com/scylladb/gemini
 
-go 1.12
+go 1.20
 
 require (
 	github.com/briandowns/spinner v1.23.0
@@ -23,4 +23,26 @@ require (
 	gopkg.in/inf.v0 v0.9.1
 )
 
+require (
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.2.0 // indirect
+	github.com/fatih/color v1.7.0 // indirect
+	github.com/golang/protobuf v1.5.3 // indirect
+	github.com/golang/snappy v0.0.4 // indirect
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
+	github.com/mattn/go-colorable v0.1.2 // indirect
+	github.com/mattn/go-isatty v0.0.8 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
+	github.com/prometheus/client_model v0.3.0 // indirect
+	github.com/prometheus/common v0.42.0 // indirect
+	github.com/prometheus/procfs v0.9.0 // indirect
+	github.com/rogpeppe/go-internal v1.10.0 // indirect
+	github.com/scylladb/go-reflectx v1.0.1 // indirect
+	github.com/spf13/pflag v1.0.5 // indirect
+	go.uber.org/atomic v1.7.0 // indirect
+	golang.org/x/sys v0.7.0 // indirect
+	golang.org/x/term v0.7.0 // indirect
+	google.golang.org/protobuf v1.30.0 // indirect
+)
+
 replace github.com/gocql/gocql => github.com/scylladb/gocql v1.7.3