feat: add support for configuring use_fips_sts_endpoint in sigv4 config

Using `AWS_USE_FIPS_ENDPOINT` to configure FIPS endpoint usage no longer
works (see prometheus/prometheus#16752). This
must be done using the `use_fips_sts_endpoint` config option added in
prometheus/common#649. It is also available in
the new sigv4 package: https://github.com/prometheus/sigv4.

Fixes #7986

Signed-off-by: Sam McBroom <[email protected]>

Author: sam-mcbr

.github/workflows/cspell.json

@@ -417,6 +417,8 @@
     "authzed",
     "resolv",
     "finalizer",
-    "selfsigned"
+    "selfsigned",
+    "FIPS",
+    "FIPSSTS"
   ]
-}
+}

Documentation/api-reference/api.md

@@ -18481,6 +18481,19 @@ string
 <p>roleArn defines the named AWS profile used to authenticate.</p>
 </td>
 </tr>
+<tr>
+<td>
+<code>useFIPSSTSEndpoint</code><br/>
+<em>
+bool
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>useFIPSSTSEndpoint defines FIPS mode for AWS STS endpoint.
+It requires Prometheus &gt;= v2.54.0.</p>
+</td>
+</tr>
 </tbody>
 </table>
 <h3 id="monitoring.coreos.com/v1.StorageSpec">StorageSpec