Deploy serverless functions to digitalocean in golang

I am trying to build a CRUD in digital ocean serverless functions. I am testing with sqlite3 and insert into the table. When I tried to deploy it to productions, I am getting errors. Here is my code:

package main

import (
    "database/sql"
    "fmt"
    _ "github.com/mattn/go-sqlite3"
)

func Main(args map[string]interface{}) map[string]interface{} {
db, err := sql.Open("sqlite3", "./data.db")
checkErr(err)

// insert
stmt, err := db.Prepare("INSERT INTO userinfo(username, departname, created) values(?,?,?)")
checkErr(err)

res, err := stmt.Exec("rumi", "CSE", "2012-12-09")
checkErr(err)

id, err := res.LastInsertId()
checkErr(err)

fmt.Println(id)

db.Close()

msg := make(map[string]interface{})
msg["body"] = id
return msg
}

Errors I am getting:

➜  functions git:(master) ✗ doctl serverless deploy . --remote-build
Deploying '/home/rumi/go/src/github.com/manjurulhoque/digitalocean-cloud-functions/functions'
  to namespace 'fn-b799454253a-a40440-4639-937f-05102a48c06e'
  on host 'https://fa45as-sgp1-18b45c02afgc.doserverless.co'
Submitted action 'blog/createBlog' for remote building and deployment in runtime go:default (id: b3d5421ee5656bb44c4295421eebb44c642cf)
Submitted action 'sample/hello' for remote building and deployment in runtime go:default (id: b3d5421ee5656bb44c4295421eebb44c642cf)
Submitted action 'blog/db' for remote building and deployment in runtime go:default (id: edcc9eefce9f4aa58c9eefce9f2aa5e6)
Transcript of remote build session for action 'blog/db':
Output of failed build in /tmp/slices/builds/fn-b79956253a-a4080-465639-95637f-05102a48c06e/blog_db/2022-10-22T04-23-08.642Z/packages/blog/db
initializing modules
go: creating new go.mod: module exec
go: to add module requirements and sums:
        go mod tidy
building
db.go:6:2: no required module provides package github.com/mattn/go-sqlite3; to add it:
        go get github.com/mattn/go-sqlite3


Deployed functions ('doctl sbx fn get <funcName> --url' for URL):
  - blog/createBlog
  - sample/hello
Failures:
Error: While deploying action 'blog/db': './build.sh' exited with code 1

project.yml

environment: {}
parameters: {}
packages:
  - name: blog
    environment: {}
    parameters: {}
    annotations: {}
    functions:
      - name: db
        binary: false
        main: ''
        runtime: 'go:default'
        web: true
        parameters: {}
        environment: {}
        annotations: {}
        limits: {}

I didn't find any good resource though to connect to DB. Any help would be appreciated.