CHANGELOG.md: Fix MD040 warnings

The following warnings are generated by using markdownlint analysis:
```
MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
```
Refer to markdown-lint [1] to fix MD040
[1]: https://github.com/updownpress/markdown-lint/blob/master/rules/040-fenced-code-language.md

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: Ia2464d3309541710d44ce3004e642a714362a36d
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8bd602f..50536bc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -41,7 +41,7 @@
    performed using the [Coccinelle semantic patch][coccinelle]
    `get_fru_record_by_option_check.cocci`:
 
-   ```
+   ```text
    $ spatch \
       --sp-file=${LIBPLDM_DIR}/evolutions/current/get_fru_record_by_option_check.cocci \
       --in-place \