README.md: Fix MD041 warnings

The following warnings are generated by using markdownlint analysis:
```
MD041/first-line-heading/first-line-h1 First line in a file should be a top-level heading [Context: "## Building the Code"]
```
Refer to markdown-lint [1] to fix MD041
[1]: https://github.com/updownpress/markdown-lint/blob/master/rules/041-first-line-h1.md

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: Ia94296369f6e778b5efadd5042c5922989a2581f
1 file changed
tree: d1cd61047d27434d840a677cd9b2ed1fc50e1dc0
  1. dump/
  2. subprojects/
  3. watchdog/
  4. .clang-format
  5. .gitignore
  6. .shellcheck-ignore
  7. checkstop_app.cpp
  8. LICENSE
  9. meson.build
  10. meson.options
  11. OWNERS
  12. README.md
  13. watchdog_timeout.cpp
README.md

openpower-debug-collector

Building the Code

To build this package, do the following steps:

    1. meson build
    2. ninja -C build

To clean the repository run `rm -rf build`.