Add versions to all the dependencies so they are pinned (#5887)

* Pinning dependency versions

* Update gradle version.

* Revert "Update gradle version."

This reverts commit 7bf787f2dcb1c2d2ce6a626104f91b5fd13ca1c1.

.ci.yaml

diff --git a/.ci.yaml b/.ci.yaml
index a8fa7a5..7504373 100644
--- a/.ci.yaml
+++ b/.ci.yaml
@@ -13,7 +13,7 @@
     properties:
       dependencies: >
         [
-          {"dependency": "curl"}
+          {"dependency": "curl", "version": "version:7.64.0"}
         ]
       device_type: none
       os: Linux
@@ -21,7 +21,7 @@
     properties:
       dependencies: >
         [
-          {"dependency": "certs"}
+          {"dependency": "certs", "version": "version:9563bb"}
         ]
       device_type: none
       os: Windows
@@ -37,7 +37,7 @@
       version_file: flutter_master.version
       dependencies: >
         [
-          {"dependency": "vs_build"}
+          {"dependency": "vs_build", "version": "version:vs2019"}
         ]
 
   - name: Windows win32-platform_tests stable
@@ -49,7 +49,7 @@
       channel: stable
       dependencies: >
         [
-          {"dependency": "vs_build"}
+          {"dependency": "vs_build", "version": "version:vs2019"}
         ]
 
   - name: Windows windows-build_all_plugins master
@@ -62,7 +62,7 @@
       version_file: flutter_master.version
       dependencies: >
         [
-          {"dependency": "vs_build"}
+          {"dependency": "vs_build", "version": "version:vs2019"}
         ]
 
   - name: Windows windows-build_all_plugins stable
@@ -74,7 +74,7 @@
       channel: stable
       dependencies: >
         [
-          {"dependency": "vs_build"}
+          {"dependency": "vs_build", "version": "version:vs2019"}
         ]
 
   - name: Windows plugin_tools_tests