Test: Fix utest fail for StUtimeInMicroseconds. v7.0.20 (#4218)

```
../../../src/utest/srs_utest_st.cpp:27: Failure
Expected: (st_time_2 - st_time_1) <= (100), actual: 119 vs 100
[  FAILED  ] StTest.StUtimeInMicroseconds (0 ms)
```

Maybe github's vm, running the action jobs, is slower. I notice this
error happens frequently, so let the UT pass by increase the number.

---------

Co-authored-by: Haibo Chen <[email protected]>
Co-authored-by: winlin <[email protected]>

Author: 3 people

trunk/doc/CHANGELOG.md

@@ -7,6 +7,7 @@ The changelog for SRS.
 <a name="v7-changes"></a>
 
 ## SRS 7.0 Changelog
+* v7.0, 2024-10-31, Merge [#4218](https://github.com/ossrs/srs/pull/4218): fix Unit test: StUtimeInMicroseconds. v7.0.20 (#4218)
 * v7.0, 2024-10-31, Merge [#4216](https://github.com/ossrs/srs/pull/4216): fix hls error when stream has extension. v7.0.19 (#4216)
 * v7.0, 2024-10-15, Merge [#4160](https://github.com/ossrs/srs/pull/4160): RTC2RTMP: Fix screen sharing stutter caused by packet loss. v7.0.18 (#4160)
 * v7.0, 2024-10-15, Merge [#3979](https://github.com/ossrs/srs/pull/3979): ST: Use clock_gettime to prevent time jumping backwards. v7.0.17 (#3979)

trunk/src/core/srs_core_version7.hpp

@@ -9,6 +9,6 @@
 
 #define VERSION_MAJOR       7
 #define VERSION_MINOR       0
-#define VERSION_REVISION    19
+#define VERSION_REVISION    20
 
 #endif

trunk/src/utest/srs_utest_st.cpp

@@ -22,9 +22,9 @@ VOID TEST(StTest, StUtimeInMicroseconds)
 	EXPECT_GT(st_time_1, 0);
 	EXPECT_GT(st_time_2, 0);
 	EXPECT_GE(st_time_2, st_time_1);
-	// st_time_2 - st_time_1 should be in range of [1, 100] microseconds
+	// st_time_2 - st_time_1 should be in range of [1, 150] microseconds
 	EXPECT_GE(st_time_2 - st_time_1, 0);
-	EXPECT_LE(st_time_2 - st_time_1, 100);
+	EXPECT_LE(st_time_2 - st_time_1, 150);
 }
 
 static inline st_utime_t time_gettimeofday() {