update image to 2.6.2

[wey-gu]

No description provided.

[wey-gu]

This pr will also help docker desktop 4.3.0+ from crashing graphD

[HarrisChu]

I think it would be confused, why branch is 2.6.0 and image version is 2.6.2?

[wey-gu]

Sure, should we create a new branch instead?

And if we leave it unchanged, in a big chance, new users will use the 2.6.0 image even from the 2.6.2 documentation, when they are running it on 4.3.0 or newer docker desktop(linux VM is cgroupv2 based), graphD will crash as RAM Utils assumed OS are cgroupv1 😭, this will make fresh user down in their first expression.

What do you think @HarrisChu , please?

We may keep it as is(2.6.0 branch but with 2.6.2 image) to avoid doc change, but in the future, we may only create branches in x.y(3.0) instead of x.y.z(3.0.0) in nebula-docker-compose.

[wey-gu]

Created a pr to guide user to find minor versions of images: #106

[HarrisChu]

prefer 2.6 branch, and declare version variable in .env file, it's the latest nebula version by default.
but we have 2.0.1 branch before, may change a lot

[wey-gu]

I will create 2.6 branch later and change all corresponding parts(readme, documentations), later

[wey-gu]

@HarrisChu v2.6 is with the same base of v2.6.0 now and the pr was requested to v2.6 now.

I will update the master README after this is merged.

[wey-gu]

left the image-v2.6.2 not being deleted as this temp branch was shared to a user for saving him from being crashed during docker desktop 4.3.0+ compose-up...