docs: update suppression schema version (#8136)

Author: nhumblot

src/site/markdown/general/suppression.md

@@ -6,7 +6,7 @@ A sample suppression file would look like:
 
 ```xml
 <?xml version="1.0" encoding="UTF-8"?>
-<suppressions xmlns="https://jeremylong.github.io/DependencyCheck/dependency-suppression.1.3.xsd">
+<suppressions xmlns="https://jeremylong.github.io/DependencyCheck/dependency-suppression.1.4.xsd">
    <suppress>
       <notes><![CDATA[
       file name: some.jar
@@ -26,7 +26,7 @@ HTML version of the report. The other common scenario would be to ignore all CVE
 
 ```xml
 <?xml version="1.0" encoding="UTF-8"?>
-<suppressions xmlns="https://jeremylong.github.io/DependencyCheck/dependency-suppression.1.3.xsd">
+<suppressions xmlns="https://jeremylong.github.io/DependencyCheck/dependency-suppression.1.4.xsd">
     <suppress>
         <notes><![CDATA[
         This suppresses a CVE identified by OSS Index using the vulnerability name and packageUrl.
@@ -98,7 +98,7 @@ It is also possible to set an expiration date for a suppression rule:
 
 ```xml
 <?xml version="1.0" encoding="UTF-8"?>
-<suppressions xmlns="https://jeremylong.github.io/DependencyCheck/dependency-suppression.1.3.xsd">
+<suppressions xmlns="https://jeremylong.github.io/DependencyCheck/dependency-suppression.1.4.xsd">
     <suppress until="2020-01-01Z">
         <notes><![CDATA[
         Suppresses a given CVE for a dependency with the given sha1 until the current date is 1 Jan 2020 or beyond.