[polybar] Remove papersdue script date invocation

Removed unnecessary invocations of date util, since it will be invoked
by the actual running script anyways.

polybar/.config/polybar/scripts/poly-papersdue

@@ -1,8 +1,8 @@
 #!/usr/bin/env sh
 
 while true; do
-  all="$(bib-due -u "$(date --date='fri this week' +%Y-%m-%d)" | wc -l)"
-  required="$(bib-due -u "$(date --date='fri this week' +%Y-%m-%d)" -p1 | wc -l)"
+  all="$(bib-due -u 'fri this week' | wc -l)"
+  required="$(bib-due -u 'fri this week' -p1 | wc -l)"
 
   # add polybar formatting to color required readings red
   # https://github.com/polybar/polybar/wiki/Formatting#format-tags