Update python-libjuju version to 2.9.42.4

Change-Id: I9770e1647ea715d205d06cd07fda1b4d244a673f
Signed-off-by: Guillermo Calvino <guillermo.calvino@canonical.com>
diff --git a/requirements.in b/requirements.in
index 0195351..68d077a 100644
--- a/requirements.in
+++ b/requirements.in
@@ -13,7 +13,7 @@
 #     limitations under the License.
 charset-normalizer
 google-auth<2.18.0
-juju==3.0.0
+juju==2.9.42.4
 kubernetes
 motor
 pyasn1
diff --git a/requirements.txt b/requirements.txt
index 53808d1..be6032c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -42,7 +42,7 @@
     #   kubernetes
 idna==3.4
     # via requests
-juju==3.0.0
+juju==2.9.42.4
     # via -r requirements.in
 jujubundlelib==0.5.7
     # via theblues