Propagate tags via par_*** macros (#112)

diff --git a/subpar.bzl b/subpar.bzl
index 3b4524c..9146e00 100644
--- a/subpar.bzl
+++ b/subpar.bzl
@@ -213,6 +213,7 @@
     default_python_version = kwargs.get("default_python_version", "PY2")
     visibility = kwargs.get("visibility")
     testonly = kwargs.get("testonly", False)
+    tags = kwargs.get("tags", [])
     parfile(
         compiler = compiler,
         compiler_args = compiler_args,
@@ -224,6 +225,7 @@
         testonly = testonly,
         visibility = visibility,
         zip_safe = zip_safe,
+        tags = tags,
     )
 
 def par_test(name, **kwargs):
@@ -241,6 +243,7 @@
     default_python_version = kwargs.get("default_python_version", "PY2")
     visibility = kwargs.get("visibility")
     testonly = kwargs.get("testonly", True)
+    tags = kwargs.get("tags", [])
     parfile_test(
         compiler = compiler,
         default_python_version = default_python_version,
@@ -251,4 +254,5 @@
         testonly = testonly,
         visibility = visibility,
         zip_safe = zip_safe,
+        tags = tags,
     )