patch 8.1.2112: build number for ConPTY is outdated

Problem:    Build number for ConPTY is outdated.
Solution:   Update to new build number. (Nobuhiro Takasaki, closes #5014)
diff --git a/src/os_win32.c b/src/os_win32.c
index 790f75e..26005b2 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -7277,7 +7277,7 @@
  * Confirm until this version.  Also the logic changes.
  * insider preview.
  */
-#define CONPTY_INSIDER_BUILD	    MAKE_VER(10, 0, 18990)
+#define CONPTY_INSIDER_BUILD	    MAKE_VER(10, 0, 18995)
 
 /*
  * Not stable now.