Update vips versions in CircleCI Dockerfile & refactor CircleCI config to use matrix

.circleci/Dockerfile

@@ -12,7 +12,7 @@ RUN \
   mkdir /root/vips \
   && cd /root/vips \
   && curl -s -S -L -o vips_releases.json "https://api.github.com/repos/libvips/libvips/releases" \
-  && for VIPS_VERSION in "8.7" "8.8" "8.9"; do \
+  && for VIPS_VERSION in "8.8" "8.9" "8.10"; do \
     mkdir $VIPS_VERSION \
     && export VIPS_RELEASE=$(grep -m 1 "\"tag_name\": \"v$VIPS_VERSION." vips_releases.json | sed -E 's/.*"v([^"]+)".*/\1/') \
     && echo "Building Vips $VIPS_RELEASE as $VIPS_VERSION" \

.circleci/config.yml

@@ -8,62 +8,16 @@ workflows:
       - lint:
           requires:
             - checkout_code
-          go_version: "1.14"
-          vips_version: "8.9"
+          go_version: "1.15"
+          vips_version: "8.10"
       - build:
-          name: go1.14_vips8.9
+          name: go<< matrix.go_version >>_vips<< matrix.vips_version >>
           requires:
             - checkout_code
-          go_version: "1.14"
-          vips_version: "8.9"
-      - build:
-          name: go1.14_vips8.8
-          requires:
-            - checkout_code
-          go_version: "1.14"
-          vips_version: "8.8"
-      - build:
-          name: go1.14_vips8.7
-          requires:
-            - checkout_code
-          go_version: "1.14"
-          vips_version: "8.7"
-      - build:
-          name: go1.13_vips8.9
-          requires:
-            - checkout_code
-          go_version: "1.13"
-          vips_version: "8.9"
-      - build:
-          name: go1.13_vips8.8
-          requires:
-            - checkout_code
-          go_version: "1.13"
-          vips_version: "8.8"
-      - build:
-          name: go1.13_vips8.7
-          requires:
-            - checkout_code
-          go_version: "1.13"
-          vips_version: "8.7"
-      - build:
-          name: go1.12_vips8.9
-          requires:
-            - checkout_code
-          go_version: "1.12"
-          vips_version: "8.9"
-      - build:
-          name: go1.12_vips8.8
-          requires:
-            - checkout_code
-          go_version: "1.12"
-          vips_version: "8.8"
-      - build:
-          name: go1.12_vips8.7
-          requires:
-            - checkout_code
-          go_version: "1.12"
-          vips_version: "8.7"
+          matrix:
+            parameters:
+              go_version: ["1.15", "1.14", "1.13"]
+              vips_version: ["8.10", "8.9", "8.8"]
 
 executors:
   imgproxy: