fix: Adds "grep -P" to the list of banned commands (#1064)

Co-authored-by: James Hegedus <jthegedus@hey.com>

test/banned_commands.bats

@@ -3,25 +3,28 @@
 load test_helpers
 
 banned_commands=(
-    realpath
-    # readlink on OSX behaves differently from readlink on other Unix systems
-    readlink
-    # It's best to avoid eval as it makes it easier to accidentally execute
-    # arbitrary strings
-    eval
+    # Process substitution isn't POSIX compliant and cause trouble
+    "<("
     # Command isn't included in the Ubuntu packages asdf depends on. Also not
     # defined in POSIX
     column
-    # does not work on alpine and should be grep -i either way
+    # echo isn't consistent across operating systems, and sometimes output can
+    # be confused with echo flags. printf does everything echo does and more.
+    echo
+    # It's best to avoid eval as it makes it easier to accidentally execute
+    # arbitrary strings
+    eval
+    # grep -y does not work on alpine and should be "grep -i" either way
     "grep.* -y"
+    # grep -P is not a valid option in OSX.
+    "grep.* -P"
+    # realpath not available by default on OSX.
+    realpath
+    # readlink on OSX behaves differently from readlink on other Unix systems
+    readlink
     # sort --sort-version isn't supported everywhere
     "sort.*-V"
     "sort.*--sort-versions"
-    # echo isn't consistent across operating systems, and sometimes output can
-    # be confused with echo flags. printf does everything echo does and more.
-    echo
-    # Process substitution isn't POSIX compliant and cause trouble
-    "<("
     # source isn't POSIX compliant. . behaves the same and is POSIX compliant
     source
 )