build(deps): bump securesystemslib from 0.26.0 to 0.27.0 in /install (#550)

Bumps [securesystemslib](https://github.com/secure-systems-lab/securesystemslib) from 0.26.0 to 0.27.0.
- [Release notes](https://github.com/secure-systems-lab/securesystemslib/releases)
- [Changelog](https://github.com/secure-systems-lab/securesystemslib/blob/main/CHANGELOG.md)
- [Commits](secure-systems-lab/securesystemslib@v0.26.0...v0.27.0)

---
updated-dependencies:
- dependency-name: securesystemslib
  dependency-type: indirect
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

install/requirements.txt

@@ -345,9 +345,9 @@ requests==2.28.2 \
     # via
     #   sigstore
     #   tuf
-securesystemslib==0.26.0 \
-    --hash=sha256:41c7b25c52dc0bafe774413b5738bbf4431f094e72a091e83d9921901972ae4c \
-    --hash=sha256:a8fa49831d6a7e48f81050984ddfac3713af0c326f558727113533edb5ca8eac
+securesystemslib==0.27.0 \
+    --hash=sha256:27fab4aae9adaf82530dc58f8e85a546f637d5ec5c5ef00d261689985420a70b \
+    --hash=sha256:7ba326a41f980b3897356663144f6091531bf3d4e8333b821164526ce8e9f48d
     # via
     #   sigstore
     #   tuf