make sure uint32_t is defined

[chillenb]

Added #include <cstdint> to builder_context.h to fix the following compile error:

CXX    annotate.o
In file included from /home/chillenb/src/buildit/include/builder/builder_base.h:8,
                 from /home/chillenb/src/buildit/include/builder/builder.h:3,
                 from /home/chillenb/src/buildit/src/builder/annotate.cpp:1:
/home/chillenb/src/buildit/include/builder/builder_context.h:25:9: error: ‘uint32_t’ does not name a type
   25 |         uint32_t size;
      |         ^~~~~~~~
/home/chillenb/src/buildit/include/builder/builder_context.h:11:1: note: ‘uint32_t’ is defined in header ‘<cstdint>’; this is probably fixable by adding ‘#include <cstdint>’
   10 | #include <unordered_set>
  +++ |+#include <cstdint>
   11 | #include <vector>

[AjayBrahmakshatriya]

Hey @chillenb thanks a lot for the changes. I am guessing cstdint was included indirectly through some standard library on my system/gcc installation.

Howevery, one of the checks failed for your PR because github has discontinued support for Ubuntu 20.04 runners. I have updated the CI scripts. Could you pull the changes from master and update the PR?

Thanks!

[chillenb]

Sure, I just rebased and it should work now!

[AjayBrahmakshatriya]

Looks good to me! Thanks for the contribution!