Add /proc/interrupts support

[Dentrax]

Signed-off-by: Furkan furkan.turkal@trendyol.com

I have some use-cases for this implementation:

• want to parse my /proc/interrupts file using procfs package (with go:linkname)
• move interrupt parsing logic from node_exporter to here
• also supports single values

All tests passes.

[Dentrax]

I was manually update the fixture so it fails. Now just followed Updating Test Fixtures instructions but I couldn't get exactly:

$ make fixtures/.unpacked
make: *** No rule to make target `fixtures/.unpacked'.  Stop.

$ make test
>> extracting fixtures testdata/fixtures
./ttar -C testdata/ -x -f testdata/fixtures.ttar
WARNING sed unable to handle null bytes, using Python (slow).

I almost waited ~5-10m but nothing happens, the process hangs, I guess. (macOS)

Feel free to commit my branch to update fixture!

Edit: It seems tests are now passing.

[discordianfish]

LGTM

[SuperQ]

Minor nit about copyright dates. Otherwise LGTM.

[SuperQ]

Just need to update the dates.

[Dentrax]

Just need to update the dates.

Done!