arrow

GH-34257:[Docs] Update git links/branches from master to main for external projects (#34502)

As shown in [#34257](https://github.com/apache/arrow/issues/34257), this pull request update the branch in our doc from **master**  to **main** for the external dependencies who have changed their default branch to main.

**What changes are included in this PR?**
9 files.
changed link's git repos:
https://github.com/conda-forge/snappy-feedstock
https://github.com/googleapis/google-cloud-cpp
https://github.com/google/highwayhash
https://github.com/dotnet/sourcelink
https://github.com/dotnet/runtime
https://github.com/numpy/numpy
https://github.com/tidyverse/dplyr
https://github.com/apache/orc

**Are these changes tested?**
no
* Closes: #34257

Authored-by: Junming Chen <junming.chen.r@outlook.com>
Signed-off-by: Weston Pace <weston.pace@gmail.com>