Move protobuf dep to a more applicable section of setup.py (#9786)

Our `protobuf` dep was in the section of `setup.py` which we delineate
as expecting all future versions of it to be compatible. However, this
is no longer actually the case, and in e4fe839
we restricted it to major vesion 4.

core/setup.py

@@ -61,6 +61,7 @@
         # with major versions in each new minor version of dbt-core.
         "click>=8.0.2,<9.0",
         "networkx>=2.3,<4.0",
+        "protobuf>=4.0.0,<5",
         "requests<3.0.0",  # should match dbt-common
         # ----
         # These packages are major-version-0. Keep upper bounds on upcoming minor versions (which could have breaking changes)
@@ -79,7 +80,6 @@
         # ----
         # Expect compatibility with all new versions of these packages, so lower bounds only.
         "packaging>20.9",
-        "protobuf>=4.0.0,<5",
         "pytz>=2015.7",
         "pyyaml>=6.0",
         "daff>=1.3.46",