Add Optional.Publisher for Rx from operator (#18)

Author: yuzushioh

Data/operators.csv

@@ -28,7 +28,7 @@ first,"first, tryFirst",
 flatMap,flatMap,
 flatMapFirst,❌,
 flatMapLatest,switchToLatest,
-from,❌,
+from(optional:),Optional.Publisher(_ output:),
 groupBy,❌,
 ifEmpty(default:),replaceEmpty(with:),
 ifEmpty(switchTo:),❌,Could be achieved with composition - replaceEmpty(with: publisher).switchToLatest()

README.md

@@ -76,7 +76,7 @@ It's based on the following blog post: [https://medium.com/gett-engineering/rxsw
 | flatMap               | flatMap                                  |                                                                                                          |
 | flatMapFirst          | ❌                                        |                                                                                                          |
 | flatMapLatest         | switchToLatest                           |                                                                                                          |
-| from                  | ❌                                        |                                                                                                          |
+| from(optional:)       | Optional.Publisher(_ output:)            |                                                                                                          |
 | groupBy               | ❌                                        |                                                                                                          |
 | ifEmpty(default:)     | replaceEmpty(with:)                      |                                                                                                          |
 | ifEmpty(switchTo:)    | ❌                                        | Could be achieved with composition - replaceEmpty(with: publisher).switchToLatest()                      |