fix: Don't let deprecated test targets get matched by '...' (#3045)

This fixes "target '//foo_test' is deprecated: Use 'foo.test' instead.
The '*_test' target will be removed in the next major release." being
warned about once per `compile_pip_requirement` call when running `bazel
test ...`.

Work towards #2976

python/private/pypi/pip_compile.bzl

diff --git a/python/private/pypi/pip_compile.bzl b/python/private/pypi/pip_compile.bzl
index 78b681b..2e3e530 100644
--- a/python/private/pypi/pip_compile.bzl
+++ b/python/private/pypi/pip_compile.bzl
@@ -196,4 +196,5 @@
         name = "{}_test".format(name),
         actual = ":{}.test".format(name),
         deprecation = "Use '{}.test' instead. The '*_test' target will be removed in the next major release.".format(name),
+        tags = ["manual"],
     )