Updated firefox packages fix security vulnerabilities

Updated firefox packages fix security vulnerabilities: Due to a missing bounds check on shared memory read in the parent process, a content process could have modified shared memory relating to crash reporting information, crash itself, and cause an out-of-bound write. This could have caused memory corruption and a potentially exploitable crash (CVE-2020-6796). If a tag was used in a tag, the parser could be confused and allow JavaScript parsing and execution when it should not be allowed. A site that relied on the browser behaving correctly could suffer a cross-site scripting vulnerability as a result (CVE-2020-6798). Memory safety bugs present in Firefox ESR 68.4. Some of these bugs showed evidence of memory corruption and presumably some of these could have been exploited to run arbitrary code (CVE-2020-6800). Also, nspr has been updated to 4.25 and nss to 3.50.0