Right-align benchmark results [Skip CI]

Author: nblumhardt

README.md

@@ -111,7 +111,7 @@ ngs":{"N":[{"Format":"x8","Rendering":"0000007b"}]}}
 See `test/Serilog.Formatting.Compact.Tests/FormattingBenchmarks.cs`.
 
 |                           Method |     Median |    StdDev | Scaled |
-|--------------------------------- |----------- |---------- |------- |
+|--------------------------------- |----------: |---------: |------: |
 |                JsonFormatter1000 | 10.9891 ms | 0.4127 ms |   1.00 |
 |         CompactJsonFormatter1000 |  5.9689 ms | 0.0556 ms |   0.54 |
 |        RenderedJsonFormatter1000 | 13.5988 ms | 0.0846 ms |   1.24 |