Update boto3 requirement in /src/release-notifier (#169)

Updates the requirements on [boto3](https://github.com/boto/boto3) to permit the latest version.
- [Release notes](https://github.com/boto/boto3/releases)
- [Commits](https://github.com/boto/boto3/compare/1.43.43...1.43.48)

---
updated-dependencies:
- dependency-name: boto3
  dependency-version: 1.43.48
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/release-notifier/requirements.txt

@@ -1,2 +1,2 @@
 slack_sdk>=3.43.0,<4.0
-boto3>=1.43.43
+boto3>=1.43.48

src/ring-scheduler/requirements.txt

@@ -1,2 +1,2 @@
-boto3>=1.43.43
+boto3>=1.43.48
 requests>=2.34.2

src/slack-bot/requirements.txt

@@ -1,2 +1,2 @@
 slack_bolt>=1.29.0,<2.0
-boto3>=1.43.43
+boto3>=1.43.48