[x/blog] content: fix images on mobile for pkgsite-redesign.article
[x/blog] content: fix images on mobile for pkgsite-redesign.article

The "height" attribute is removed from <img> tags so that images will
scale gracefully as the viewport width becomes narrower than the
original image size.

For golang/go#42493

Change-Id: I951a1d82a119f55d22cd564e871203d07a0a5f28
Reviewed-on: https://go-review.googlesource.com/c/blog/+/270804
Trust: Julie Qiu <8d32267b6b4884cf35adeaccde2b6857ae11aace@golang.org>
Run-TryBot: Julie Qiu <8d32267b6b4884cf35adeaccde2b6857ae11aace@golang.org>
TryBot-Result: Go Bot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>
X-Blog-Commit: 5d7660a8674f3c659ded6a2f49c151c26c5eb282

golang/website,golang/website,golang/website,golang/website,golang/website,golang/website,golang/website