[Snyk] Security upgrade alpine from 3.16 to 3

This PR was automatically created by Snyk using the credentials of a real user.

Keeping your Docker base image up-to-date means you’ll benefit from security fixes in the latest version of your chosen image. #### Changes included in this PR - Dockerfile We recommend upgrading to `alpine:3`, as this image has only 0 known vulnerabilities. To do this, merge this pull request, then verify your application still works as expected. --- **Note:** _You are seeing this because you or someone else with access to this repository has authorized Snyk to open fix PRs._ For more information: 🧐 [View latest project report](https://app.snyk.io/org/tenable.cs-cloud-security/project/e29ec924-c326-4d23-a764-b7a33125df99?utm_source=github&utm_medium=referral&page=fix-pr) 🛠 [Adjust project settings](https://app.snyk.io/org/tenable.cs-cloud-security/project/e29ec924-c326-4d23-a764-b7a33125df99?utm_source=github&utm_medium=referral&page=fix-pr/settings) [//]: # 'snyk:metadata:{"prId":"858e3ad3-c87b-4ac4-ba50-c34774cfda69","prPublicId":"858e3ad3-c87b-4ac4-ba50-c34774cfda69","dependencies":[{"name":"alpine","from":"3.16","to":"3"}],"packageManager":"dockerfile","projectPublicId":"e29ec924-c326-4d23-a764-b7a33125df99","projectUrl":"https://app.snyk.io/org/tenable.cs-cloud-security/project/e29ec924-c326-4d23-a764-b7a33125df99?utm_source=github&utm_medium=referral&page=fix-pr","type":"auto","patch":[],"vulns":[],"upgrade":[],"isBreakingChange":false,"env":"prod","prType":"fix","templateVariants":["updated-fix-title"],"priorityScoreList":[],"remediationStrategy":"vuln"}' --- **Learn how to fix vulnerabilities with free interactive lessons:** 🦉 [Learn about vulnerability in an interactive lesson of Snyk Learn.](https://learn.snyk.io/?loc=fix-pr)

tenable / terrascan-action

[Snyk] Security upgrade alpine from 3.16 to 3 #87