Incubator-superset: Date is not coming in proper format in partition chart

[xxsacxx]

While using partition chart with BigQuery as data source the date which is of format "2020-05-27" i.e yyyy-mm-dd in superset gets displayed as epoch time.
While running the same query on sqllab,bigquery or csv export from superset give it in proper format (yyyy-mm-dd)

Expected results

expected "date" to be displayed in "yyyy-mm-dd"

Actual results

date is getting displayed in epoch format

Screenshots

How to reproduce the bug

1. Creating a date column in format "yyyy-mm-dd"
2. 
3. Sqllab and csv export from superset gives the date in proper format i.e "yyyy-mm-dd"

Environment

(please complete the following information):

• superset version: superset version --- 0.35.1
• python version: python --version ---- 3.6.9
• node.js version: node -v
• npm version: npm -v

Checklist

Make sure these boxes are checked before submitting your issue - thank you!

• [ ] I have checked the superset logs for python stacktraces and included it here as text if there are any.
• [ ] I have reproduced the issue with at least the latest released version of superset.
• [ ] I have checked the issue tracker for the same issue and I haven't found one similar.

Additional context

Add any other context about the problem here.

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[eugeniamz]

It reproduce with other databases too. Thanks for reporting it!

[xxsacxx]

It reproduce with other databases too. Thanks for reporting it!

What are the next steps,here?

[willbarrett]

We have confirmed that this is a bug on the current master branch. As this is an open source project, we do not have SLAs for fixing bugs. An existing contributor may contribute a patch for this issue, or we are happy to review pull requests from the broader community. If you'd like to attempt a fix, we are happy to point you in the right direction.

[xxsacxx]

If you'd like to attempt a fix, we are happy to point you in the right direction.
@willbarrett sure should I start with this?

[willbarrett]

You are most likely correct. @villebro would you mind providing some guidance to @xxsacxx on where in that massive file to start? You're quite familiar with its inner secrets.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions. For admin, please label this issue .pinned to prevent stale bot from closing the issue.