Revert "Fix rapids-date-string (#68)" (#70)

This reverts commit #68, which unintentionally broke some things in CI.

tools/rapids-date-string

@@ -1,25 +1,9 @@
 #!/bin/bash
 # A utility script produces a date string
 
-# TODO: remove default value after calling scripts are updated
-FORMAT_ARG="${1:-second}"
-
-case "${FORMAT_ARG}" in
-  day)
-    FORMAT="%y%m%d"
-    ;;
-  second)
-    FORMAT="%s"
-    ;;
-  *)
-    rapids-echo-stderr "Invalid format argument: ${FORMAT_ARG}"
-    exit 1
-    ;;
-esac
-
-RAPIDS_DATE_STRING="$(date +${FORMAT})"
+RAPIDS_DATE_STRING="$(date +%y%m%d)"
 if [ "${GITHUB_ACTIONS:-false}" = "true" ]; then
   WORKFLOW_DATE=$(rapids-retry gh run view "${GITHUB_RUN_ID}" --json createdAt | jq -r '.createdAt')
-  RAPIDS_DATE_STRING=$(date -d "${WORKFLOW_DATE}" +${FORMAT})
+  RAPIDS_DATE_STRING=$(date -d "${WORKFLOW_DATE}" +%y%m%d)
 fi
 export RAPIDS_DATE_STRING

tools/rapids-env-update

@@ -8,4 +8,4 @@ rapids-configure-conda-channels
 
 source rapids-configure-sccache
 
-source rapids-date-string day
+source rapids-date-string