erofs-utils: drop known issue in README

Since lz4-1.9.3 has been released,
https://github.com/lz4/lz4/releases/tag/v1.9.3

Move this lz4hc issue (lz4 <= 1.9.2) to "Comments" instead.

Link: https://lore.kernel.org/r/20201121022623.3882-1-hsiangkao@aol.com
Reviewed-by: Li Guifu <bluce.lee@aliyun.com>
Signed-off-by: Gao Xiang <hsiangkao@aol.com>
diff --git a/README b/README
index 5addd6b..7a7ac5d 100644
--- a/README
+++ b/README
@@ -19,7 +19,7 @@
 Dependencies
 ~~~~~~~~~~~~
 
- lz4-1.8.0+ for lz4 enabled [2], lz4-1.9.0+ recommended
+ lz4-1.8.0+ for lz4 enabled [2], lz4-1.9.3+ recommended [4].
 
 How to build for lz4-1.9.0 or above
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -48,7 +48,7 @@
 	yum install lz4-static.x86_64
 
 However, it's not recommended to use those versions since there were bugs
-in these compressors, see [2] [3] as well.
+in these compressors, see [2] [3] [4] as well.
 
 How to generate erofs images
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -70,19 +70,6 @@
 
  $ mkfs.erofs -E legacy-compress -zlz4hc foo.erofs.img foo/
 
-
-Known issues
-~~~~~~~~~~~~
-
-1. LZ4HC cannot compress long zeroed buffer properly with
-   LZ4_compress_HC_destSize()
-   https://github.com/lz4/lz4/issues/784
-
-   which has been resolved in
-   https://github.com/lz4/lz4/commit/e7fe105ac6ed02019d34731d2ba3aceb11b51bb1
-
-   and will be included in lz4-1.9.3 if all goes well.
-
 Obsoleted erofs.mkfs
 ~~~~~~~~~~~~~~~~~~~~
 
@@ -149,3 +136,13 @@
     version as well) or backport all stable bugfixes to old stable versions,
     e.g. our unoffical lz4 fork: https://github.com/erofs/lz4
 
+[4] LZ4HC didn't compress long zeroed buffer properly with
+    LZ4_compress_HC_destSize()
+    https://github.com/lz4/lz4/issues/784
+
+    which has been resolved in
+    https://github.com/lz4/lz4/commit/e7fe105ac6ed02019d34731d2ba3aceb11b51bb1
+
+    and already included in lz4-1.9.3, see:
+    https://github.com/lz4/lz4/releases/tag/v1.9.3
+