Update README with recently added / changed options

In particular, remove reference to the deprecated `--tojson` option.

README.md

@@ -260,14 +260,15 @@ Flags:
   -C, --colors                force print with colors
   -e, --exit-status           set exit status if there are no matches or null or false is returned
   -f, --front-matter string   (extract|process) first input as yaml front-matter. Extract will pull out the yaml content, process will run the expression against the yaml content, leaving the remaining data intact
+      --header-preprocess     Slurp any header comments and seperators before processing expression. This is a workaround for go-yaml to persist header content. This flag will be removed once this feature has been out in the wild for a while. (default true)
   -h, --help                  help for yq
   -I, --indent int            sets indent level for output (default 2)
   -i, --inplace               update the yaml file inplace of first yaml file given.
   -M, --no-colors             force print with no colors
   -N, --no-doc                Don't print document separators (---)
   -n, --null-input            Don't read input, simply evaluate the expression given. Useful for creating yaml docs from scratch.
+  -o, --output-format string  [yaml|y|json|j|props|p] output format type. (default "yaml")
   -P, --prettyPrint           pretty print, shorthand for '... style = ""'
-  -j, --tojson                output as json. Set indent to 0 to print json in one line.
       --unwrapScalar          unwrap scalar, print the value with no quotes, colors or comments (default true)
   -v, --verbose               verbose mode
   -V, --version               Print version information and quit