README.md: fix revision history whitespace

Fix the right-hand-side whitespace in the revision history table.

Cc: Bob Feng <[email protected]>
Cc: Liming Gao <[email protected]>
Cc: Michael D Kinney <[email protected]>
Cc: Rebecca Cran <[email protected]>
Cc: Yuwei Chen <[email protected]>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=991
Signed-off-by: Laszlo Ersek <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Liming Gao <[email protected]>

Author: Laszlo Ersek

README.md

@@ -229,5 +229,5 @@ Copyright (c) 2008-2017, Intel Corporation. All rights reserved.
 |            | Add !error statement section                                                                                                                                                                                                                                                                                                                                        |               |
 |            | [#1110](https://bugzilla.tianocore.org/show_bug.cgi?id=1110) Extend exclamation statement's keyword to case-insensitive                                                                                                                                                                                                                                             |               |
 |            | [#598](https://bugzilla.tianocore.org/show_bug.cgi?id=598) update supported operators in 8.2.4.6 Expressions                                                                                                                                                                                                                                                        |               |
-| 1.29       | [#1453](https://bugzilla.tianocore.org/show_bug.cgi?id=1453) Update Build spec to remove EDK related contents                                                                                                                                                                                                                                                                                                                        | Mar 2019      |
-| 1.30       | [#1952](https://bugzilla.tianocore.org/show_bug.cgi?id=1952) Update Build spec to support HOST_APPLICATION MODULE_TYPE                                                                                                                                                                                                                                              | July 2019      |
+| 1.29       | [#1453](https://bugzilla.tianocore.org/show_bug.cgi?id=1453) Update Build spec to remove EDK related contents                                                                                                                                                                                                                                                       | Mar 2019      |
+| 1.30       | [#1952](https://bugzilla.tianocore.org/show_bug.cgi?id=1952) Update Build spec to support HOST_APPLICATION MODULE_TYPE                                                                                                                                                                                                                                              | July 2019     |