[EngCom] Public Pull Requests - 2.2-develop

Accepted Public Pull Requests:
 - magento/magento2#12105: #11936:required attribute set id filter on attribute group repository getList (by @tzyganu)
 - magento/magento2#12751: magento/magento2#12439 Newsletter subscription success email not sent… (by @Styopchik)
 - magento/magento2#12737: magento/magento2#11953: Product configuration creator does not warn about invalid SKUs (by @zamoroka)
 - magento-engcom/magento2ce#1016: #11743: [GitHub] AbstractPdf - ZendException font is not set (by @serhii-balko)
 - magento/magento2#12636: #12625: Add Current Date to update_time Field for Block and Pages (by @osrecio)
 - magento/magento2#11686:  Fix error when generating urn catalog for empty misc.xml (by @tdgroot)
 - magento/magento2#11878: [BUGFIX] Made method public so a plugin is possible. (by @dheesbeen)
 - magento/magento2#11462: #7241: Always add empty option for prefix and/or suffix if optional (by @avstudnitz)


Fixed GitHub Issues:
 - magento/magento2#11936: required attribute set id filter on attribute group repository getList (reported by @tzyganu) has been fixed in magento/magento2#12105 by @tzyganu in 2.2-develop branch
   Related commits:
     1. 433c3cd9
     2. 7be92a87

 - magento/magento2#12439: Newsletter subscription success email not sent after confirmation (reported by @nfourteen) has been fixed in magento/magento2#12751 by @Styopchik in 2.2-develop branch
   Related commits:
     1. c4e4168c

 - magento/magento2#11953: Product configuration creator does not warn about invalid SKUs (reported by @JanisE) has been fixed in magento/magento2#12737 by @zamoroka in 2.2-develop branch
   Related commits:
     1. 5cf0d348
     2. 7418f1ac

 - magento/magento2#11743: AbstractPdf - ZendException font is not set (reported by @jchenevey) has been fixed in magento-engcom/magento2ce#1016 by @serhii-balko in 2.2-develop branch
   Related commits:
     1. 2629726d
     2. b326714b
     3. 5f4363b2
     4. 9ce4730d

 - magento/magento2#12625: when saving a page in magento 2.2.1, 'Modified' date field is not getting updated (reported by @mahmood537) has been fixed in magento/magento2#12636 by @osrecio in 2.2-develop branch
   Related commits:
     1. 22f454dd

 - magento/magento2#5188: Error generating URN-catalog when blank one exists (reported by @JamesonNetworks) has been fixed in magento/magento2#11686 by @tdgroot in 2.2-develop branch
   Related commits:
     1. 177e5409
     2. 0d652139
     3. a781bf6f
     4. dcc480d1
     5. 5d4e1c29
     6. b552dd1b
     7. b85b91e4

 - magento/magento2#7241: No option to start with blank option for prefix and suffix in checkout. (reported by @spyrule) has been fixed in magento/magento2#11462 by @avstudnitz in 2.2-develop branch
   Related commits:
     1. 11e38f68
     2. 7800e5dd
     3. 252529f0
     4. 519b805c
     5. eb79b38b
     6. fce3afe6
     7. 3e38118c