Add PULL_REQUEST_TEMPLATE.md to npmignore

[pkuczynski]

I dedicate any and all copyright interest in this software to the
public domain. I make this dedication for the benefit of the public at
large and to the detriment of my heirs and successors. I intend this
dedication to be an overt act of relinquishment in perpetuity of all
present and future rights to this software under copyright law.

Anyone is free to copy, modify, publish, use, compile, sell, or
distribute this software, either in source code form or as a compiled
binary, for any purpose, commercial or non-commercial, and by any
means.

[dchest]

Thanks for noticing that it's in npm! But I'll probably just move everything to .github and add it into npmignore.

[pkuczynski]

Sure, whatever is easiest for you :)