Use latest version of elastalert

[iwilltry42]

This PR updates the Dockerfile to use the latest version of yelp/elastalert.

There were some caveats though regarding the used Python version.
yelp/elastalert is now built using Python 3(.6).

When using alpine:latest as py-ea, one will get Alpine:3.10, where apk add python3 will be Python 3.7.4, which is not available in Alpine 3.9 which node:alpine is based upon.
That's why I'm pinning the Python version to exact python=3.6.8-r2 which exists in both.

I tested this image on our production cluster and can confirm that it works as expected.

[iwilltry42]

Closed, because there are more sophisticated PRs already.

[nickthegreek89]

Hello,

@iwilltry42, which are these sophisticated PRs you mentioned?

Additionally, did your Dockerfile that was changed in this PR work with the new yelp/elastalert version?

BR,
Nick

[iwilltry42]

@nickthegreek89 maybe not more sophisticated, but with the same result/goal:

#117 & #122 which are still open.

And yes, I'm using it at the moment with elastalert v0.2.1 so it works with Elasticsarch v7.4.1 for me 👍

[nickthegreek89]

Ok @iwilltry42, thanks a lot for the update! Will probably give a try to your Dockerfile and see how it goes!

BR,
Nick