Update prereqs to include bc command

Dockerfile

@@ -3,7 +3,7 @@ FROM bitnami/kubectl:1.22
 USER root
 
 RUN apt-get update && \
-    apt-get install -y git && \
+    apt-get install -y git bc && \
     rm -r /var/lib/apt/lists /var/cache/apt/archives 
 
 RUN mkdir -p /tmp/krew && chown 1001 /tmp/krew 

check_full_pvs.sh

@@ -21,7 +21,10 @@ checkReqs () {
     echo "ERROR: df-pv kubectl plugin is required for this script to run. First install krew, then install df-pv plugin."
     exit 
   fi
-
+  if [ ! -x "$(command -v "bc")" ]; then
+    echo "ERROR: bc command (precision calculator) is required for this script to run."
+    exit
+  fi
 }
 
 scaleworkload () {