[Snyk] Security upgrade golang from 1.20.1 to 1.21

[DvirDukhan]

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 `golang:1.21`, as this image has only 78 known vulnerabilities. To do this, merge this pull request, then verify your application still works as expected. Some of the most important vulnerabilities in your base image include: | Severity | Priority Score / 1000 | Issue | Exploit Maturity | | :------: | :-------------------- | :---- | :--------------- | |  | **829** | Out-of-bounds Write
[SNYK-DEBIAN11-GLIBC-5927133](https://snyk.io/vuln/SNYK-DEBIAN11-GLIBC-5927133) | Mature | |  | **829** | Out-of-bounds Write
[SNYK-DEBIAN11-GLIBC-5927133](https://snyk.io/vuln/SNYK-DEBIAN11-GLIBC-5927133) | Mature | |  | **829** | Out-of-bounds Write
[SNYK-DEBIAN11-GLIBC-5927133](https://snyk.io/vuln/SNYK-DEBIAN11-GLIBC-5927133) | Mature | |  | **829** | Out-of-bounds Write
[SNYK-DEBIAN11-GLIBC-5927133](https://snyk.io/vuln/SNYK-DEBIAN11-GLIBC-5927133) | Mature | |  | **829** | Resource Exhaustion
[SNYK-DEBIAN11-NGHTTP2-5953384](https://snyk.io/vuln/SNYK-DEBIAN11-NGHTTP2-5953384) | Mature | --- **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/redislabs/project/d344bed3-09fc-4884-8a96-bc5c63d31f9f?utm_source=github&utm_medium=referral&page=fix-pr) 🛠 [Adjust project settings](https://app.snyk.io/org/redislabs/project/d344bed3-09fc-4884-8a96-bc5c63d31f9f?utm_source=github&utm_medium=referral&page=fix-pr/settings) [//]: # 'snyk:metadata:{"prId":"536799ba-bda0-46db-a0e8-a17fa985921f","prPublicId":"536799ba-bda0-46db-a0e8-a17fa985921f","dependencies":[{"name":"golang","from":"1.20.1","to":"1.21"}],"packageManager":"dockerfile","projectPublicId":"d344bed3-09fc-4884-8a96-bc5c63d31f9f","projectUrl":"https://app.snyk.io/org/redislabs/project/d344bed3-09fc-4884-8a96-bc5c63d31f9f?utm_source=github&utm_medium=referral&page=fix-pr","type":"auto","patch":[],"vulns":["SNYK-DEBIAN11-GLIBC-5927133","SNYK-DEBIAN11-NGHTTP2-5953384"],"upgrade":["SNYK-DEBIAN11-GLIBC-5927133","SNYK-DEBIAN11-GLIBC-5927133","SNYK-DEBIAN11-GLIBC-5927133","SNYK-DEBIAN11-GLIBC-5927133","SNYK-DEBIAN11-NGHTTP2-5953384"],"isBreakingChange":false,"env":"prod","prType":"fix","templateVariants":["updated-fix-title","priorityScore"],"priorityScoreList":[829,829],"remediationStrategy":"vuln"}' --- **Learn how to fix vulnerabilities with free interactive lessons:** 🦉 [Resource Exhaustion](https://learn.snyk.io/lesson/redos/?loc=fix-pr)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (9578098) 82.74% compared to head (ec642c9) 82.74%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #177 +/- ## ======================================= Coverage 82.74% 82.74% ======================================= Files 7 7 Lines 591 591 ======================================= Hits 489 489 Misses 59 59 Partials 43 43 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.