patch 8.1.2182: test42 seen as binary by git diff

Problem:    Test42 seen as binary by git diff.
Solution:   Add .gitattributes file.  Make explicit that 'cpo' does not
            contain 'S'. (Daniel Hahler, closes #5072)
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..9216dbe
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1 @@
+src/testdir/test42.in diff
diff --git a/Filelist b/Filelist
index e79cbb7..a2b9f0a 100644
--- a/Filelist
+++ b/Filelist
@@ -4,6 +4,7 @@
 # source files for all source archives
 SRC_ALL =	\
 		.gitignore \
+		.gitattributes \
 		.hgignore \
 		.lgtm.yml \
 		.travis.yml \
diff --git a/src/testdir/test42.in b/src/testdir/test42.in
index c35569a..1d9d3ab 100644
--- a/src/testdir/test42.in
+++ b/src/testdir/test42.in
Binary files differ
diff --git a/src/version.c b/src/version.c
index 0fff97d..afdc49a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2182,
+/**/
     2181,
 /**/
     2180,