README: tone down the warning about tc-lib-pdf (#589)

* README: tone down the warning about tc-lib-pdf

Signed-off-by: Ruben Barkow-Kuder <github@r.z11.de>

* Update README.md

Co-authored-by: William Desportes <williamdes@wdes.fr>

---------

Signed-off-by: Ruben Barkow-Kuder <github@r.z11.de>
Co-authored-by: William Desportes <williamdes@wdes.fr>

README.md

@@ -12,9 +12,8 @@
 * **source**      https://github.com/tecnickcom/TCPDF
 
 
-## IMPORTANT
-A new version of this library is under development at https://github.com/tecnickcom/tc-lib-pdf and as a consequence this version will not receive any additional development or support.
-This version should be considered obsolete, new projects should use the new version as soon it will become stable.
+## NOTE
+A new version of this library is under development at https://github.com/tecnickcom/tc-lib-pdf and as a consequence this library is in support only mode.