Fix typo in test file name added in commit 4909b38af0.

Author: Shlok Kyal <shlok.kyal.oss@gmail.com>
Backpatch-through: 13
Discussion: https://postgr.es/m/CANhcyEXsObdjkjxEnq10aJumDpa5J6aiPzgTh_w4KCWRYHLw6Q@mail.gmail.com

contrib/test_decoding/Makefile

@@ -9,7 +9,7 @@ REGRESS = ddl xact rewrite toast permissions decoding_in_xact \
 ISOLATION = mxact delayed_startup ondisk_startup concurrent_ddl_dml \
 	oldest_xmin snapshot_transfer subxact_without_top concurrent_stream \
 	twophase_snapshot catalog_change_snapshot skip_snapshot_restore \
-	invalidation_distrubution
+	invalidation_distribution
 
 REGRESS_OPTS = --temp-config $(top_srcdir)/contrib/test_decoding/logical.conf
 ISOLATION_OPTS = --temp-config $(top_srcdir)/contrib/test_decoding/logical.conf