BUG: Add missing channel pinnings

[carterbox]

I believe that in order for the new stdlib template to work on staged recipes, c_stdlib also needs to be defined in the pinnings because I was trying to build locally and I got the following error:

    Encountered problems while solving:
      - nothing provides requested c_linux-64 2.17.*
    
    Could not solve for environment specs
    The following package could not be installed
    └─ c_linux-64 2.17.*  does not exist (perhaps a typo or a missing channel).

until I added the pinnings in this PR.

(base) bash-5.1$ conda list "conda*"                                                                                                                          
# packages in environment at /home/DCHING/miniforge3:                                                                                                         
#                                                                                                                                                             
# Name                    Version                   Build  Channel                                                                                            
conda                     24.3.0          py311h38be061_0    conda-forge
conda-build               24.3.0          py311h38be061_1    conda-forge
conda-forge-pinning       2024.05.02.11.25.06      hd8ed1ab_0    conda-forge
conda-index               0.4.0              pyhd8ed1ab_0    conda-forge
conda-libmamba-solver     24.1.0             pyhd8ed1ab_0    conda-forge
conda-package-handling    2.2.0              pyh38be061_0    conda-forge
conda-package-streaming   0.9.0              pyhd8ed1ab_0    conda-forge
conda-smithy              3.35.0             pyhd8ed1ab_0    conda-forge

#26206
conda-forge/conda-forge-pinning-feedstock#5499

[conda-forge-webservices]

Hi! This is the friendly automated conda-forge-linting service.

I was trying to look for recipes to lint for you, but couldn't find any.
Please ping the 'conda-forge/core' team (using the @ notation in a comment) if you believe this is a bug.

[h-vetinari]

Yes, this looks very reasonable, thank you! Can we leave out all the whitespace changes though please even if the formatting is not ideal / inconsistent...?