README instruction `make build_analysis_image` not valid anymore

[dimakuv]

In the Local Analysis section, there is this text:

package-analysis/README.md

Lines 104 to 105 in 91bb7de

	`gcr.io/ossf-malware-analysis/analysis`. This can be built with
	`make build_analysis_image`, or the public images can be used instead.

The make build_analysis_image is stale though. This makefile target was replaced in this commit: c473e2d

So the correct target now is build/image/analysis.