Bump to v5.1.0-rc1+dev68 and update ReadMe

Small edit to REVISION version comment in osapi-version.h

README.md

@@ -10,6 +10,18 @@ The autogenerated OSAL user's guide can be viewed at <https://github.com/nasa/cF
 
 ## Version History
 
+### Development Build: 5.1.0-rc1+dev68
+
+- When `OS_DEBUG` is enabled, this adds a message if mutex give/take actions occur outside the expected sequence. This informs the user (via the debug console) if a lock is taken more than once or if a lock is given by a different task than the one that originally took it:
+```
+OS_MutSemTake():216:WARNING: Task 65547 taking mutex 327685 while owned by task 65547
+```
+- Removes all FIXME comments
+- Resolves security/filename race issue by opening file and acting on descriptor by adding fstat stub
+- Squashed the minor recommended bugs
+- UtAssert macros now accept variable string arguments.The `UtAssert_True` wrapper around call is no longer needed to accommodate dynamic string output, thus removing the double assert. UtAssert macros will now be able to offer more information by themselves.
+- See <https://github.com/nasa/osal/pull/639>
+
 ### Development Build: 5.1.0-rc1+dev60
 
 - Appliy standard formating, whitespace-only changes

src/os/inc/osapi-version.h

@@ -30,17 +30,16 @@
 /*
  * Development Build Macro Definitions
  */
-#define OS_BUILD_NUMBER   60
+#define OS_BUILD_NUMBER   67
 #define OS_BUILD_BASELINE "v5.1.0-rc1"
 
 /*
  * Version Macro Definitions
  */
 #define OS_MAJOR_VERSION 5 /*!< @brief ONLY APPLY for OFFICIAL releases. Major version number. */
 #define OS_MINOR_VERSION 0 /*!< @brief ONLY APPLY for OFFICIAL releases. Minor version number. */
-#define OS_REVISION                                                                                         \
-    99 /*!< @brief ONLY APPLY for OFFICIAL releases. Revision version number. If set to "99" it indicates a \
-          development version.  */
+#define OS_REVISION      99 /*!< @brief ONLY APPLY for OFFICIAL releases. Revision version number. A value of "99" indicates an unreleased development version.  */
+
 #define OS_MISSION_REV 0 /*!< @brief ONLY USED by MISSION Implementations. Mission revision */
 
 /*