Contributor numbers: Do not show non-integer axis labels

[imphil]

In the Project metrics of projects we show the number of contributors over time. Look at the Y axis in this image:

We need to configure the plotting library to only show full contributors, not fractions of them 😄

[imphil]

Also put less numbers on the x axis.

[mrmayurgithub]

Sir, I would like to contribute. But I am new to open source, so can you help me out by giving a certain direction ?
Like where in the project can I correct this issue.

[wallento]

This issue is harder than #338 and I suggest you focus on that one for now

[mrmayurgithub]

harder

OK, Sir.

[sanjibansg]

I would like to contribute to this issue, will be grateful for guidance to approach this. @imphil