Merge pull request #4768 from h-vetinari/proto4

close out protobuf 4.23.3 migration; drop protobuf 3.21

recipe/conda_build_config.yaml

@@ -151,7 +151,9 @@ zip_keys:
   -
     - arrow_cpp
     - libarrow
-  # until libprotobuf 3.21->4.23 migration is complete
+  # as of 4.23.x, libprotobuf requires patch-level run-exports;
+  # we couple it with grpc (which very roughly releases in sync)
+  # to reduce the migration pain for these two libs a bit.
   -
     - libgrpc
     - libprotobuf
@@ -465,7 +467,7 @@ libgit2:
 libgoogle_cloud:
   - '2.12'
 libgrpc:
-  - '1.54'
+  - '1.56'
 libhugetlbfs:
   - 2
 libhwy:
@@ -495,7 +497,7 @@ libpcap:
 libpng:
   - 1.6
 libprotobuf:
-  - '3.21'
+  - 4.23.3
 libpq:
   - 15
 libraw: