Panic when custom templates are available with long paths

[David]

When a custom template is present on the system isntruments -s templates will include it in the list twith the full path, e.g. "~/Library/Application Support/Instruments/Templates/my-template-name.tracetemplate" which breaks the assumption of max 64 chars long template names. The result is a panic when running cargo instruments --list.

[Colin Rofls]

@dvdplm 0.3.1 is released, thanks for the issue!