ignore non-json lines in cargoBuildLog

[felschr]

Fix issues with non-JSON values in cargoBuildLog by ignoring non-json lines.

Motivation

In some cases using cargo with message-format=json prints some non-json lines: rust-lang/cargo#8179

When that's the case crane currently fails with:

searching for bins/libs to install from cargo build log at cargoBuildLogGbmv.json
parse error: Invalid numeric literal at line 390, column 6

Checklist

• added tests to verify new behavior
• added an example template or updated an existing one
• updated docs/API.md (or general documentation) with changes
• updated CHANGELOG.md

[ipetkov]

Thanks for the contribution @felschr, overall looks good to me!

Are you interested in adding a test case for this to make sure we don't regress?

[felschr]

Here we go, does this look good to you?

[ipetkov]

Looks great, thanks again!