use 32 bit compatible pack() format

[staabm]

should fix #125

[staabm]

code inspired by

https://github.com/kelunik/two-factor/blob/65da89746b2220fa5740a97a1e07799b37d13535/src/Oath.php#L58

[coveralls]

Coverage remained the same at 100.0% when pulling 7757438 on staabm:patch-1 into 1438831 on Spomky-Labs:v9.0.

[staabm]

I was not able to verify thix fix still works for php 64bit, as I dont have it available on my machine. lets see what the unit tests think.

in my 32bit installation at least I can generate OTP values now, which wasn't possible before.

[Spomky]

Hi,

Thank your for this PR.
Can you have a look at #107? It looks like this PR is the reason for this issue.
If it works fine on your 32bits env, I will revert that PR

[staabm]

thx for the fast reply. after reverting the change of #107 it works for me.

[Spomky]

Should be fixed in v9.1.3.
Feel free to open another issue if there is something wrong with this new release.