Update tilt ubuntu image to 22.04 to fix glibc issue

Signed-off-by: Anshul Ahuja <anshul.ahu@gmail.com>

Tiltfile

@@ -110,7 +110,7 @@ local_resource(
 
 # Note: we need a distro with a bash shell to exec into the Velero container
 tilt_dockerfile_header = """
-FROM ubuntu:focal as tilt
+FROM ubuntu:22.04 as tilt
 
 RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -qq -y ca-certificates tzdata && rm -rf /var/lib/apt/lists/*
 
@@ -218,7 +218,7 @@ def enable_provider(provider):
 
     # Note: we need a distro with a shell to do a copy of the plugin binary
     tilt_dockerfile_header = """
-    FROM ubuntu:focal as tilt
+    FROM ubuntu:22.04 as tilt
     WORKDIR /
     COPY --from=tilt-helper /start.sh .
     COPY --from=tilt-helper /restart.sh .